I use Picassa web (Google pictures). I find a picture of my pattern or scan my copy and save the photo to my google photo album. I save the pictures from anywhere I can find them - ebay, the pattern companies, whatever. Each photo it identified by the pattern name. Then I add info about the pattern. I usually indicate it it has been cut, cut apart, whether or not I have made it, and any changes I have made.
This lets me look through all my patterns easily. If I see one that I'm interested in, I click on it and see if there are any notes.
This is my first tip. Please tell me how I can make it better. I write worse than I sew.