Looking for Answers about Nikon Inc. AF NIKKOR 28mm f/2.8D?

Yes

Nikon offers two types of autofocus digital camera bodies: those with a built-in focus drive motor and those which require a lens to have a motor. Cameras such as the D60 do not have a focus motor in it so they require the lens to have the focusing motor – an “AF-S” lens. While these bodies can use a lens with no focus motor (an “AF” lens) you would have to manually turn the focus ring to bring the subject in to sharp focus.

Yes it will.

This lens will NOT auto focus with the D40. The D40 requires AF-S lenses for auto focus.

Nikon offers two types of autofocus digital camera bodies: those with a built-in focus drive motor and those which require a lens to have a motor. Cameras such as the D3100 do not have a focus motor in it so they require the lens to have the focusing motor – an “AF-S” lens. While these bodies can use a lens with no focus motor (an “AF” lens) you would have to manually turn the focus ring to bring the subject in to sharp focus.

No Auto Focus function with D3000.

yes

No it will not auto focus, your camera requires lenses with an AF-S designation.

Yes

Yes, but obviously no autofocus. The 28mm f/2.8 AI-S would be a great alternative.

Yes, the D90 has a built in screw drive.

The AF NIKKOR 28mm f/2.8D can be use with D3100. However, autofocus will not work because neither the D3100 nor the AF NIKKOR 28mm f/2.8D has an autofocus motor.