I can concur - my backups used to take 1 - 2 minutes. Since 10.5.6 I havn't had a successful backup. The current one has been running since 10am. It's now 12:40pm.
The f/w 2.2 significantly fixed my backup issues (and broke most applications, even official Apple ones, but that's a different story)... now it's worse than before.
I'll try and reboot my iPhone as suggested above and post back.