Personally--no idea, not a bike mechanic. Looking at Sheldon's site and elsewhere, it looks like an ISIS drive. Octalink doesn't spline the full length. I did something about 8 and 10 spline versions of... something, already forgot.

I do know the BB is hollow, and it's a 3 piece crank setup.

Edit: thanks for posting the pic, darn work filters block tinypic on me.