As you read in my previous post, the other site I use racked me up a ton of cash and a lot of points, enough to buy an iPod touch which I'm using now. There are many great iPhone/ipod touch apps, a few of the great free ones are:
Aim
Myspace
Facebook
Twitterfon
Trace
Labyrith
Pandora
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I reccomend all of these apps, if you would like to add any to the list, leave a comment with your favorite ones