#3. "RE: D5000 and SB-900 - can it be done wirelessly or not?" In response to In response to 0
Welcome to Nikonians, Nate!
As the others have said, the D5000 does not have the "Commander Mode" in its built-in flash that would allow it to control an off-camera Speedlight wirelessly; it can only be used manually in "SU-4 Mode".
Regarding the manuals, I guess you need to know what to look for, but the D5000 manual does not suggest anywhere that the camera can control slave Speedlights wirelessly. It does state that "CLS-compatible" Speedlights are supported, but then goes on to describe how they can be used on-camera, not off-camera.