Bella's Book Club
http://bellabookclub.blogspot.com/

Funny Fiction for Teens
http://www.ala.org/ala/mgrps/divs/yalsa/teenreading/trw/trw2007/booklists07.cfm

Get Graphic
http://www.getgraphic.org/

Guysread.com
http://www.guysread.com/

Noflyingnotights.com
http://www.noflyingnotights.com/index2.html

Readergirlx.com
http://www.readergirlz.com/manifesta.html

Readersclub
http://www.plcmc.org/readers_club/default.asp

Readingrants.org
http://readingrants.org/

Smartgirl.org
http://www.smartgirl.org/

Teenlink
http://teenink.com/

Teenreads.com
http://www.teenreads.com/

YALSA (Young Adult Library Services Association) See this for lots more great book lists.
http://www.ala.org/ala/mgrps/divs/yalsa/booklistsawards/booklistsbook.cfm

Wordsmiths
http://teenlink.nypl.org/WordSmiths-Current.cfm