Yeah, itunes radio is awesome. theres a channel even for metalheads and hardcore junkies.
the only problem is if you have slow Internet, you might get chopped up audio due to the slow buffering.
Xypher: No its free, as long as you have iTunes.
kerplunk182: Yeah i love pod casts, theres this awesome pod cast i recommend.
Dave's Lounge - down tempo, trip-hop stuff and i think the host's really cool.
I don't really ever stick to one station but, these are just some of the frequents which i reckon plays a good choice of stuff.
Rock > High Voltage (post-hardcore & a bit of metal here & there)
Alternative > Indie 103.1
International > Japan-a-radio (awesome anime song & jrock & jrock)
Jazz > IceburgRadio.com - The Right Note
Jazz > IdealSound.ca ::iDS001: Frozen Beats
Jazz > radioReal Jazz
Electronic > BassDrive (good, drum&bass stuff)
Pop > Indie Airplay (they play more indie electronica)
Pop > 181.fm - Awesome 80s
Pop > 181.fm - 80's Hairbands
Pop > 181.fm - Star 90s
Dime: AND YESSSS, i completely second that!