I just fixed a problem with my iPod touch that happened after I installed the 1.1.3 jailbreak. The events in my calendars were shifted by 5 hours. Finally, I found out that the iPod touch has a time zone option for its clock, and a separate time zone option for the calendars. My clock was set to Toronto time (which is right), but the calendar was incorrectly set to London time. It's an easy fix, but I could see some users having the same problem.