Yup, TuneIn is a MUST app for anyone, I've used it for a couple of years now on my Android phone, and it's pretty much replaced Netflix for me while in the car (still have Unlimited Verizon plan, so can stream all day if I want). 

Also what I like is they have more than just streaming music in their catalogs, you can listen to amateur radio repeaters, police frequencies, streaming radio stations from across the world (LBC 97.3 in London, WBAI in NYC, and WUSB in Stoneybrook being my faves) , not to mention other streams from SomaFM and more.

So yup, if you don't already use this, get it now... I grabbed the Pro version on Nexus 7 since I had the $25 gift card, but the freebie one is nice too, that's still what I use on my phone.