Have a collection of vinyl records that you're looking to transfer to .mp3? There are a host of hardware options (external sound cards, USB turntables) and software options that will help you do this. Beware: I've known people that have tried this and be prepared to spend a lot of time getting it right / convert.
Personally, I have no desire to undertake this task as the process seems too arduous and the end result is a file that loses the essence of why I collect vinyl records. Sure it's portable and playable across different devices but, for me, the convenience of having everything in digital format doesn't outweigh the experience and sound quality that records provide. That's just me.
If you're interested in taking this on for your own collection, Wired has a great "how to" wiki that will show you how to do this.