Wild Apricot blogs about nonprofits setting up Facebook for the first time.
DIOSA also blogs about MySpace 101.
FYI, there are groups, fan pages and causes at Facebook. The current recommendation I’m hearing is to set up a group. Fan pages might have more functionality, and causes are tailored to nonprofits, but Facebook users are more attuned to using the popular ‘groups’ application so it probably makes sense to start there–you can set up a group under your own profile.
UPDATE: Now (1/09) the trend is towards Fan Pages. Facebook tells how to convert from a group to a page. There’s a 1200-member limit on groups, pages can be found via internet search by those NOT on FB, and there’s messaging capability at Fan Pages–although Groups allow you to send invites to your friends. Still, I’m seeing ‘Can’t decide? Use both!” Here’s a comparison from a business article.