Right now (ending August 31) WritersMarket.com is having a special. You can subscribe monthly for 5.99, one year for 29.99 (normally 39.99), and for two years for 44.99 (normally 54.99). (via Guide To Literary Agents) The one-year code is 1YRAUG10 and the two-year code is 2YRAUG10.
I'm leary of spending money for a book I haven't finished yet, but at the same time, I really do think that *this* time, I'm going to do it. I'm thinking about just going for the two years.
Anyway, if you hadn't heard about the special, and it's something you're interested in, here you go! (Feel free to let me know if you subscribe, or if you think I should or shouldn't!)