Try something like Microsoft Excel, the Open Office spreadsheet, etc. Then print out some hard copies for the safe, upload it to an online storage site, and load it on a flash-drive or SD memory card. Then you have multiple copies in the event of one failing. Professional, cheap, easy, and completely customizable.
BTW, this is not my idea. Someone else on this forum or HPT mentioned it in another thread. But! It's a great idea!