• www.skratchpiklz.com - Anyone who is anyone frequents the message board here regularily.  If you don't already know, the Invisibl Skratch Piklz are a group of, arguably, the best turntablists in the world.
• www.wicked-styles.com - A really good site for everything turntablism.  Online reviews, turntablism 101, etc. Everybody should go here every now and then.
• www.turntablism.com - A good site on turntablism.  The message board here used to be really popular, but nowadays most people use the board at skratchpiklz.com.

DJ Companies:

• www.stantonmagnetics.com - Stanton Magnetics.
• www.vestaxdj.com - Vestax
• www.eclerdjdivision.com - Ecler's english web site

Other Good Sites:

• www.mplayer.com - If you want to battle, perform, or just listen to other DJ's cut it up, download this program.  Really good for beginners to get used to performing and good for veterans to strut their stuff.