Spoke Size / Spoke Length Database - What size spokes do I need?

Dale, I've got a rear wheel build for you in a week or so... I wanna watch and help out tho', so I can do it myself next time... 36h Goldtech to H plus son, gonna go 3 cross with bladed spokes... Any idea what length spokes I'm gonna need? Is it gonna be easy to get black brass nipples? How's the birthday goin'? :)
how bladed? if too bladed you need the hubs eyelets slotted ;)
black brass nipples are hard to get hold of, try cavendish though. i built the 36h rear 4x with 280's and they were a tad long. i'd imagine 268ish