There's a big fat
Sticky that discusses ways of how to get music onto your iPod using either iTunes, or alternatives. And that sticky is at the top of this section. iTunes is FREE. Whereas Rhapsody Unlimited you need to pay for. iTunes organises your music by artist & album.
iTunes (click on link) But choose whatever program you prefer to do the job. There's alternatives. If anything goes wrong with your iPod & they find out you weren't using iTunes to transfer songs, then I don't think any warranty would be worth much.