I'm on both facebook and myspace. and especially on facebook, theres a list of "events" and there are TONS of authors who are always posting contests for books or e-books (as the case may be). Now I think this is great. If you are a user of facebook then you would also know that they list the upcoming events you've been invited to on the right side of your main page. This is extremely handy so you don't even have to remember them you can go as they come up and have a blast in the process.
Just thought i'd toss this out there as I know, especially with everyones wallets being so tight this would be appreciated : )