I've never tried to make mayo on my own before, but there are a number of recipes in Mark Bittman's "How To Cook Everything Vegetarian." It's pretty much my food bible.

Yep, Mark Bittman, as previous commenter noted-
http://books.google.com/books?id=3R9jAnWvesEC&lpg=PT181&ots=JYnF-13IqE&dq=mark%20bittman%20vegan%20mayo&pg=PT181#v=onepage&q&f=false

The Moosewood Cookbook has a silken tofu mayonnaise that might fit the bill. I'm sure you can google it and find the recipe on the net.

Second the Moosewood recipe.

I second the Mark Bittman recipe. You can also see reviews of this recipe here.

I have one that's super easy, cheap, and actually tastes like mayo!

http://cleangreensimple.com/2011/04/vegan-mayonnaise/

Bryanna Clark Grogan has a Vegenaise recipe that many vegan bloggers seem to swear by (particularly on the post punk kitchen website). I didn't have a lot of luck with it, but here's a link to a google doc version of it if you want to try it: https://docs.google.com/View?id=dqhrgm2_276hcpn3gc4

YEP:
http://www.food.com/recipe/vegan-mayonnaise-123538

http://vegweb.com/index.php?board=297.0