I've been putting songs onto my son's MP3 player tonight. It was easy.
First of all, ripping songs from CDs into MP3 format is legal in the USA, but not here in the UK - copyright and all that. Yes, I know it's stupid, but the law is an ass and all that.
Assuming that these are all non-copyright songs...
Use Windows Media Player on XP and select the RIP fucntion. You can then rip the tracks into your My Music folder. Plug your MP3 player in, right click on the track(s) and use the SEND TO option to send them to your MP3 player.
It was easy really.