I've finished the Leadville 100 5 times.  Last year I got sick the night before and dropped out after 20 miles.  I'm back in this year.

There's a Leadville 100 group on Yahoo It's listed as a running group but it's for the mountain bike race.  If you go back through the old posts you'll find lots of information or you can ask something new.

For training plans, I've heard very good things about Lynda Wallenfels personal training or some of her pre-made training plans. People will start with on of the base training plans and finish up with one of her 100 miler plans.

I've been working on a Leadville 100 FAQ but still have lots to finish up on it.