SocialOomph.com

I just read about a tool that lets you plan not only your Twitter posts (like HootSuite.com) but also your Facebook account. The good news with HootSuite is that it's free but so is SocialOomph.com for the Twitter piece. They do charge you for the Facebook scheduling and many other pretty cool looking features. There is a free 30-day trial for the professional version however. Here's a link to check it out (full disclosure, I did just sign up for an affiliate account): SocialOomph.com