Thanks to My Good Cents for sharing this awesome site for keeping track of mail-in rebates (MIRs).
Simply register at Rebate-Tracker.com, and then every time you have a MIR to submit, you just take a few moments to enter in all of the relevant details. The web site will organize your submissions, keep track and report on the money you are owed, and will even send you reminders when your rebates are due. It gives you a great summary of your savings and even a success ratio that shows how many rebates you have successfully redeemed.
I can't wait to try this out next time I have a rebate to submit!