Saw a link to this while looking around on Sprint's application store. It's called Skydeck.
http://www.skydeck.com/
Basically what is does is synchronize your texts, call logs (from Sprint's website (I believe)), voicemails (if you set it up) and contacts. I installed and synced it and it looks pretty slick! I know it works with Sprint but don't know about other carriers.
From their website:
Skydeck is your cell phone, online. All of your cell phone calls, text messages, voicemails, and contacts are mirrored on Skydeck.com, and you can search, read, and reply to those messages online as if you were calling or texting from your cell
phone. To find out more, visit the features page.
Always Free version
* Back up all your contacts, calls, and texts
* One click updates for your address book
* Unlimited text messaging from the web
* Automatic lookup of unknown numbers
Update: Skydeck requires a Blackberry, OS version 4.2 or later, Windows Mobile 6, or an Android phone from Verizon Wireless, AT&T, Sprint, or T-Mobile.