I just got a new Nexus S on Sunday! Took me a good 5 minutes or so to get the Bootloader unlocked, flash CWM, and flash SU for my root access. After that I just copied over my Titanium Backup folder and restored all the stuff. Give it a quick reset and then all my text messages were back! Plus all my other stuff, but I just wanted to confirm that yes Titanium Backup will restore text messages, along with whatever wireless AP's you hook to and other things you don't think about.