Verizon is launching a new $10 75MB data plan for the BlackBerry Curve 3G 9330 that limits usage to popular social networking apps like Twitter and Facebook, as well as major chat apps like BlackBerry Messenger, Google Talk, AIM, Yahoo Messenger and Windows Live.

It's a cheap plan, but it comes with a number of serious caveats: the 9330 is a year old now, and won't be compatible with BlackBerry OS 7 or RIM's upcoming BBX OS. Still, it might be worth checking out if you're only using the phone for messaging — but you might also look at AT&T's free iPhone 3GS paired with its $15 plan that offers 200MB of unrestricted data, or T-Mobile's $20 plan for unlimited texting and 200MB of data on a variety of Android devices. It's a good time for cheap cellphones.