If you can find the files in .flac format, that's probably the best -- you don't lose any sound quality at all. It's like listening to them on the CD. They're pretty big files, and to play them in iTunes or on your iPod you have to convert them to Apple Lossless format. But I know people who download FLACs as torrents from places like The Pirate Bay and such and they swear it's the best way to listen to portable music because FLACs are the best quality next to the actual CD. You could try a torrent site like that, but I don't know if you'll find The Beatles there... might be worth a look.
And in the end the love you take
Is equal to the love you make