I know most people have their own customized spreadsheets they use to keep track of all of their gear. I used to do the same, but I've written an application that helps me keep track of my gear and lets me easily build pack lists and plan trips including menus and itineraries, and thought other people might like to play around with it. I know not everyone likes to use software to keep track of backpacking equipment, and that some people already have a workable solution, this is for people who like to tinker, or aren't satisfied with their spreadsheet like I wasn't. The programs is free and available for windows 7 (I'm working on an XP version), osx, and linux, it is still in beta testing, but should be bug-free for most people. If you want the source code, let me know, I'd be happy to post it and have people improve upon it. I'd really like to see this project evolve into something that could be of use to the backpacking community.
Cheers.