I think there's an iphone/ipad app specifically for crafting stashes but I have an android phone. So I've been using evernote but it takes time because with the free account, you can only upload 60 mb per month. What I'm doing so far is making a new evernote notebook for each fabric line or category (name of the line or a name like "miscellaneous dots", etc) and then I take a picture of the fabric with a 6" ruler on it to see the scale. I use the amount of fabric as the note title so I can see at a glance how much of each fabric I have. I use comic book boards so I have them wrapped first before taking the pic. I hope it helps me to "see" my stash better and use it more.
A bonus is that I can have it with me if I'm shopping. Colors wouldn't be exact enough for matching but at least I could avoid buying a fabric I already have or one that I have something very similar of. It would be good for pattern shopping too although I mostly find patterns online these days.