Exchange 2007 will do remote wipe too, if you have corporate or hosted exchange. You can do it from Outlook Web Access.
There's also one called remotePROTECT that can do various levels of lock/kill via text message. OOPS! Sorry cchris81, I didn't see your last line before I posted! I had used remotePROTECT awhile back when I was building ROMs for the Apache, as I think (going on distant memory here) there was a way to build it right into the extended ROM so it would reinstall with your existing settings upon a hard reset. Made it really hard for someone else to use your phone.
