wide angle or a fisheye if you want the effect. But you can just do post processing in CS4.
Need a fast lense f/2.8 or faster
if you make a photo into a fisheye effect in postproduction, your stupid. if you don't have the gear, work with what you got, don't try making it look like something you don't because it will never come out nearly as good as having a real fish. many of the pictures you posted were generally poorly composed as for skateboarding photography. they just have nice lighting, and thats what makes it look "pro" even though no thought was really given into the composition.
go here. its a great place to learn about skateboarding photography. i believe julian lurks on sp too.