1:45 p.m.: Here's a pretty interesting quote from men's winner Wesley Korir via the Marathon's Facebook page.
"Near mile 20, someone shouted that I was in sixth," he said. "I knew if I went too hard, too soon, that I would cramp up. I saw the guys in front of me and I thought, 'Let me get fifth.' Then I passed the guy in fourth and I thought, 'Wow, I could get fourth.' When I saw the guy in front of him, I thought, 'Wow, I could get on the podium.'"
Get on the podium he did.
12:30 p.m.: Patriots fans will be interested to know that former linebacker Tedy Bruschi is more than a quarter of the way through the race, or 10K.
Bruschi reached the 10K mark in 1:10:37, and he's projected to complete the race with a total time of just under five hours.
12:18 p.m.: It may have been a sweep for Kenya, but American Jason Hartmann had a very strong showing in Boston.
He finished fourth in the Men's Elite division.
12:13 p.m.: Wesley Korir kept a little extra in his reserves for the last stretch, and because of that, he wins the 2012 Boston Marathon.
The Kenyan grew his lead to 14 seconds in the final half-mile or so, as he really turned it on down the stretch. He finished with an unofficial time of 2:12:40.
That also means that it's a clean sweep for the Kenyans.
12:08 p.m.: Sharon Cherop is the women's winner for 2012.
The Kenyan was able to hold off her fellow countrywoman Jemima Jelagat Sumong in a terrific ending.
Things are heating up on the men's side with just a mile to go, as Wesley Korir leads the way. Wesley Korir is going to do all he can to make it interesting, though.
12:03 p.m.: We're down to the final mile in the women's race, and Sharon Cherop is pulling away as the runners hit Boylston.
11:53 a.m.: Temperatues are in the low-to-mid 80s right now, but it doesn't appear to be taking much of a toll on Levy Matebo.
He's got about a 10-second lead right now, as he comes through Brookline.
On the women's side, it's still Cherop and Sumong battling it out up front, and they're just two miles from the finish line.
11:43 a.m.: The women have entered Cleveland Circle, as they make the left onto Beacon Street.
Sharon Cherop continues to lead, but she's got company at the head of the pack.
Both Georgina Rono and Jemim Jelagat Sumong are right there with Cherop.
Big news on the men's side, too. Defending champion Geoffrey Mutai has withdrawn from the race at the 30K mark after issues with cramping.
It's Levy Matebo and Matthew Kisorio leading as the men hit Heartbreak Hill, and Matebo just broke away actually.
11:32 a.m.: A quartet of women's runners have emerged out front as the leaders.
Sharon Cherop is followed by Firehiwot Dado, Georgina Rono and Jemima Jelagat Sumong as they begin the climb up Heartbreak Hill.
On the men's side, Mutai has fallen off the pace, with Matthew Kisorio and Levy Matebo leading the pack.
11:28 a.m.: Sheron Cherop passed the Newton Fire Station with the lead, but that didn't last too long. Caroline Kilel regained the lead shortly thereafter.
On the men's side, it's Mutai holding on to the lead, but a pack of eight or nine runners continues to run up front.
American Jason Hartmann sits 18 seconds back as the top-running American at the moment.
11 a.m.: Georgina Rono leads the women's division at the halfway point, while Mutai continues to lead through 15K on the men's side.
In wheelchair action, it was Josh Cassidy taking home the men's title. He finished the race in an incredible one hour and 18 minutes.
In the women's wheelchair race, it was Wakako Tsuchida getting the win in 1:32:01
10:35 a.m.: Glenn Randall's time at the top is short-lived. A pack has caught the American, and he's fallen back to 11th.
Geoffrey Mutai, last year's winner, is your new leader.
10:25 a.m.: American runner Glenn Randall is off to a strong start in the men's elite division.
He's out to an early lead, as he's running up front through four miles. He completed that stretch in just 19:25, and he had a 23-second lead through four miles.
Kenyan Caroline Kilel has the lead in the women's race through nine miles.
10 a.m.: The men's elite runners have crossed the starting line in Hopkinton, and their Boston Marathon has begun.
The 10 o'clock hour also signals the start of Wave 1, the first wave of "everybody else" so to speak. Early reports indicated that there certainly didn't seem to be a shortage of runners despite warnings about the hot weather that will make life miserable, especially for the less experienced runners.
9:53 a.m.: At the 5K mark, it's Caroline Rotich of Kenya leading the way in the elite women's division.
The leading American woman at the moment is Mayumi Fujita. She's right there with a pack of probably 15-20 runners that are all running up front. Fujita is just a second off of the Rotich's pace.
9:34 a.m.: The elite women's division just kicked off.
According to the marathon's Twitter feed, they did so in 80-degree weather. It's getting warmer, and it's gettin warmer quick.
9:30 a.m.: The Boston Marathon is under way.
The wheelchair division has kicked off, and we're just a couple of minutes away from the women's division opening up.
The elite women are gathering at the starting line in Hopkinton, readying for their 9:32 start
9:10 a.m.: We're just minutes away from the wheelchair division going, as they'll hit the starting line in Hopkinton at 9:17.
The elite women will follow shortly thereafter at 9:32, and the elite men (as well as Wave 1) will take off at 10.
The temperature in Hopkinton right now is 69 degrees, but that number is obviously expected to rise before the end of the day.
8:25 a.m.: The biggest storyline Monday, by far, will be the unseasonably warm temperatures expected to grip the Hub for the marathon.
At the annual prerace dinner on City Hall Plaza on Sunday night, Mayor Thomas Menino cautioned runners, giving them one last chance to think things over.
"We're asking runners who haven't run previously to think about tomorrow and maybe coming back next year," the mayor said. "We don't want have any accidents out there, or anybody overtaken by the heat."
6 a.m.: It's Patriots' Day in Boston, which means an unofficial welcome to spring and Marathon Monday.
The world's best runners, as well as a local crop of marathoners, will take to the streets today for one of the premiere distance races. They'll start in Hopkinton, Mass., then brave the hills through Newton and into Boston's Kenmore Square.
One of the big storylines this year is sure to be the heat. After a brief taste of spring/summer last month, the area has had a chilly few weeks. The weather cleared over the weekend, though, and temperatures are expected to be in the 90s for Marathon Monday. That will create a true test for the runners and their supporters alike, and race officials are warning participants to be safe.
Fans will be keeping their eyes open for Geoffrey Mutai of Kenya, who broke the world record last year by running a 2:03:02. His time has since been ruled not the record, since the Boston course has a lot of hills and quite the tailwind, but it's still the benchmark for Boston and a remarkable feat.
Caroline Kilel also returns to defend her women’s title.
The race starts at 9 a.m. for some participants, then 9:32 for the elite women and 10 for the elite men. We’ll be following the action here on NESN.com. Check in to see the latest results and stories from the Boston Marathon.