I recommend the following:
WILCO!!!, Air, Battles, Beck, Eels, Grizzly Bear, Manu Chao, Neil Young, The Unicorns, Wilco, XTC, Rodrigo y Gabriela, Plants and Animals, Why?, Animal Collective, Black Moth Super Rainbow, The Octopus Project, Cloud Cult, El Ten Eleven, The Hold Steady, Islands, Jay Reatard, Man Man, Queens of The Stone Age, The Mars Volta, Radiohead, Nine Inch Nails, The Sword, Tokyo Police Club, Ween
they're all fun, and you'll be the coolest kid at your school
BTW I'm 16 and when I was 14, I was obsessed with Wilco, The Apples In Stereo, Beck, and the Shins
and to search mediaf!re, go to google and type in
site:mediaf!re.com "Queens of The Stone Age"
except with whatever band you're looking for
and if you don't have a rapidshare account, stick with mediaf!re, because you'll encounter timers, downlaod limits, spyware, and viruses with any other server
and get an enourmous hard drive to contain all your new music
EDIT: if you want other good forums for music, I'll recommend
the sound opinions message board (
http://soundopinions.org/forum) (be careful; it's the most critical forum ever)
the avant garden (
www.alienonacid.com)
skafunkrastapunk (skafunkrastapunk.com)