what kind of headset ?
i have the same one and it spins perfect, maybe you just overtightened your compression?
edit- did you have a tough time getting the top bearing into the headtube? mine wouldnt fit and i had a really tough time getting it in...
i used anal-eezz. I had extra lying around so i decided to put some use into it
Just to make sure, did you put the bearings in right side up? I know it sounds stupid but I had a friend do that