been asking that question since I got my Samsung Focus last week - Samsung is zero help, and not even apologetic that I can't do something I've been doing for years. Microsoft amazingly claimed NO support for WP7 and suggested I call Samsung! If you hear anything about something like Dashwire or Cloud Backup apps coming to WP7 please let me know!
If you save texts to your sim Card, they transfer over, though that doesn't allow for a whole lot to be transferred, especially if you have a lot of contacts on your SIM, plus I don't know the "Import SIM" program on the WP7 takes the contacts of the SIM or not (or, rather, if your contacts would still be on your Windows Live Contacts if you removed them from your SIM). I downloaded Jeyo Mobile Companion my my pc, and then uploaded all my texts there. Now, at least I have a database of all my texts from my old phone, thought I would still prefer to have Windows create a MyPhone-esque upload/download cloud program for phones.