You'll have to do some targeting within the sites themselves, but myspace.com, facebook.com, digg.com, slashdot.org, and stumbleupon.com. You can also try advertising on college newspaper sites.
Well, yes, if you go the traditional method of banner advertising. But the real way to get traffic is with some nice guerrilla marketing.
Yes there are many young users, but you need to target them. The average age of a myspace member is now around 35 years old. http://www.comscore.com/press/release.asp?press=1019
just go to any college that u want to target, spend some time talking and be friends with them...research from within, then u'll understand and know where they hang out and which is the best place for them to surf, advertise there...setup doorway pages according to what's is in hype for them, so when they online, the first place they'll going to go is u.. heck, you can also hired them to advertise for you...but offline advertising in college will not make thing thing work, easily ruined by other competitors
definitely the best way to market your site would be through myspace. Try and advertise to certain groups through myspace.