Dunno about anyone else but:
-I ramp up to about 5k
-Release the clutch while increasing the throttle; modulate clutch to keep engine at ~ 5.5k
I have a vlsd so even if i burn out a bit it'll pick it up and i won't loose too much time; if u have a open diff however, you may want to let the clutch out a bit slower and be a bit more carefull (an open diff under burn out will produce roughly half the torque to the ground as a limited slip; w/ a limited slip i find it easier to lay down the torque just enough to chirp one of the rear tires and let the vlsd pick it up.)
The best way is to experiment, it's hard to expain a good launch but you'll know right away when you've done it right.
Sorry that was so long winded, i've been doing calculus all day again <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/crazy.gif" border="0" valign="absmiddle" alt=':crazy:'>