Music you should check out.

These are some free and legal songs from purevolume.com that have been playing on my computer:

"The Queen and I" by Gym Class Heroes - First off, they're a rap band. Secondly, this song is darn catchy. Even if you don't like rap, give it a try. To download it, you have to go to the site for this Fueled By Ramen & Decaydance Summer of 2006 Audio Sampler.

"Crazy As She Goes" by The Legion of Doom - Using The Raconteurs' "Steady As She Goes" for a base, they make a really catchy fun song. More rap, I know ... but it's good!
UPDATE: While looking at The Legion of Doom's site, I discovered that "Crazy As She Goes" is a mix of that Raconteurs song with "Crazy" by the rap group Gnarls Barkley.

"All for the Money," "Anonymous," and "Effect of the Scene" by A Billion Ernies - All of the free music on their purevolume site is fantastic. I downloaded the older songs in college and was happy to see that they've posted three new ones. They are the most creative ska(core) band I've ever heard. They do have some screaming, but they mix it with singing, horns and upbeats so well that it's something totally different from all other hardcore music.