I did find this, in an article from the Spokesman Review:
» Here's how Idaho's Democratic caucuses work:
» •Anyone willing to pledge to support a particular Democratic candidate – and not to participate in any other party's nominating process for that year's presidential election – can participate. Seventeen-year-olds can participate if they'll be 18 by the Nov. 4 general election.
» •Participants gather in a big room in each county and huddle into groups by the candidate they support, or they can choose "uncommitted." Then, each group has a representative give a speech to try to persuade others to join. People switch groups, and then the votes are tallied up.
» •Idaho's 23 delegates are divided proportionally based on the results; a candidate must get at least 15 percent of the support to secure a delegate.
» John Foster, executive director of the Idaho Democratic Party, said, "A caucus is the best example of living, breathing democracy you'll ever see. It's loud and boisterous and kinda messy, but a hell of a lot of fun."
http://www.spokesmanreview.com/idaho/story.asp?ID=220766(It would also appear from the above article that unless Edwards and Clinton supporters show up in force, there may be a blowout win for Obama here.)