I know this site is mostly geared towards audio & DJ'ing, but I think it could be cool to see tutorials focused on VJ'ing as well. .. especially since they often go hand in hand.
- reviews/tutorials of popular VJ software (ie. Vidvox VDMX, Cycling74 Max/MSP, Module8, Arkaos, Quartz Composer, etc..), hardware controllers (NuVJ, Monome, Lemur, DVDJ, Kaoss Pad Entrancer, game controllers, etc..) and other technologies and/or hardware (Miss Pinky, monitors, projectors, ..)
- technique tutorials (common and esoteric VJ setups, using video switchers, matrix switches, using various hardware and software technologies together, using Ableton Live or other sequencing software to mix AV, ..)