Great reference guide here as well, has a lot of info as well as some higher sources of protein for the vegan diet. http://www.vrg.org/nutrition/protein.php
"Vegan athletes’ protein needs can range from 0.36 to 0.86 grams of protein per pound. Protein supplements are not needed to achieve even the highest level of protein intake."
I've based mine around the 0.36 per pound for the last 3 years or so but have increased slightly with the higher amount of training I've been doing, seems to fit quite well and as Cappy and VB mentioned, if you are eating whole, natural foods it comes pretty dang easy to get.