Originally Posted by
Plecks
Well, that's a MTB hub, so unless you're building this up on a MTB frame, they probably won't fit (135mm locknut spacing on these, track frames typically have 120mm, road frames it depends on how old, but not more than 130mm). Plus, that hub is made to take a cassette, which as a SS your bike doesn't need.
If you're looking for cheap, I recommend you get a Formula hub, with fixed/fixed flip-flop for the rear. With fixed/fixed you can still put a freewheel on for coasting, but you still have the option of putting a fixed cog on there and have a lockring. They're about $40 each, and you see them all over the place (often rebranded, ala Velocity, IRO, Specialized, etc).
As for a spoke calculator, check out
http://www.sheldonbrown.com/wheelbuild.html , he has a few linked on that page (you should have Sheldon Brown's site in your bookmarks anyway).
+1 for this wealth of common sense.
If you want a singlespeed, build it up with a singlespeed hub.
Also, buy Jobst Brandt's book. It's a step by step guide to a basic 3 cross wheel. Do you have access to a truing stand, a spoke tension gauge and a wheel dishing gauge? Those will really help, so if there's a bike co-op near you, check them out.