This month's edition of the excellent show RadioLab has a feature story on RAAM. The show is called Limits and is about how far one can push their body. It starts maybe 5-8 minutes into the show, but the first short story is about cycling and the Ironman.
Here's the link: http://www.wnyc.org/shows/radiolab/. Look on the right side of the page for Limits; you can also get it as a podcast from iTunes.