Did you reinstall lately?
My 10.4.11 Drive seemes to have iTunes 7.6.2 on it, have you tried Software update to see if iTunes is listed?
Another 10.4.11 drive has iTunes 6.05 on it... I hate upgrading iTunes, seems worse at every upgrade.
The 10.5.8 drive I'm booted from now has iTunes 8.02 on it.