I found this surfing on the Sheldon Brown page, pretty cool.

http://www.sheldonbrown.com/rinard/spocalc.htm

Some of the numbers in the database are old so make sure to get up to date numbers from the Manufacturer.

_________________
I thought I was supposed to get better with practice!?!?!

There's a spoke calculator on the DT Swiss website. That's the one I used when I built my wheel.

_________________
There's a lot of shame on a road bike. -- evdog

i used both of them and took an average. then the guy at beyond talked me out of my numbers and sold me spokes that were too long.

good thing they also weren't in stock or you would have been screwed!