Nikon omitted the "H" in "HD" and called its movie mode "D-Movie". And thats correct, there's nothing "high-def" in it. I'm quite dissapointed by the actual (technical) quality of the D-Movies. I didn't expect this heavy compression artefacts and jaggies in a DSLR. Resizing to 640x360 (the default Vimeo size) is the only way to hide them. This camera loves organic shapes, faces, blur, fuzzy things but hates anything detailed and edgy. It deliveres a heartiness and quite pleasing analog feel though. If you expect HD quality or a camcorder replacement better wait for another model.
Colors look great though and what you see above is straight from the camera. By the way don't forget to lock the exposure to prevent flickering. I forget it most of the time.
I strongly suggest you try filming with the D90 yourself. Don't rely on remote diagnosis.
A good review of the D-Movie mode can be found at
luminous-landscape.com/reviews/cameras/d90.shtml
UPDATE: Thanks to clever guys you can
get rid of the stair-steps by using a Displacement Map in After Effects or Vegas but you can't do anything about the poor compression quality.
