I've been scanning my library and moving them (via OCR) to unprotected .prc for my Kindle. It is somewhat labor intensive, perhaps 15 hours per book, but it is enjoyable for me, kind of like meditation.
Once I'm finished, I have a digital copy forever. I then box them up and they go in the garage (alongside my CD collection).
As far as copyrights go, I think of it like ripping an owned CD to mp3 for use on my iPod. I'm not distributing these files, just using them on my Kindle.
Jiiri