For those not aware, that's what I did this year and last, the short version of the Iditarod Trail Invitational. The full length version is 1100 miles all the way to Nome. 3 riders and two walkers took on that challenge this year, and they're all still going, with Phil Hofstetter in the lead right now. Not far behind him are riders Tracey and Jay Petervary, with Tom Jarding leading the legendary Tim Hewitt on foot. Phil's in White Mountain right now, @80 miles from home(he lives in Nome). I've been checking the updates several times daily, and it's pretty exciting stuff. They travelled down the Yukon river, through 100 mile+ uninhabited lengths of trail, and across sea ice to get where they are now.
The message board here: http://kathih.websitetoolbox.com/ is a great way to cheer them on, as they're able to occasionally check it at schools in the villages they pass through. They're a huge morale boost for racers on the course, and I encourage you all, whether you know them or not, to post something up there letting them know people are watching with interest.
The main site for the race, with the Leader Board and Latest News updates is here: http://www.alaskaultrasport.com/alaska_ultra_home_page.html