Originally Posted by CoachMike
I recommend using a bug/issue tracker.
Something like Bugzilla or FogBugz will really help you out.
When my company installed one (we used bugzilla because it was free), it was a godsend. Of course the hard part is getting people to use a bug/issue tracker instead of just emailing you to fix a problem. Luckily this initiative was supported by upper management so it wasn't that hard.