When your new iPod Touch arrives, connect it to your computer and give it the same name as your old one. Then tell it to restore it from backup.
You do sync regularly and have backups right?
If you don't, then hook your current Touch up, let it sync and backup (could take a while if you don't do it often) and then follow the above steps.
My roommate has been using the same basic backup for the past 3 years on his iPhone (and has gone through 5 of them), he still has the first text message he ever sent (from the iPhone).