I think the D80 can autofocus all lenses, where the d40 needs AF-S lenses, but I am canon and still get confused about nikon sometimes
brb ill try to look it up
Edit:
Looks like D80 can use most/all lenses from nikon
Mount:
Nikon F mount (with AF coupling & AF contacts)
Lenses:
DX Nikkor : All functions supported
Type G or D AF Nikkor : All functions supported
Micro Nikkor 85 mm F2.8D : All functions supported except autofocus and some exposure modes
Other AF Nikkor*2 : All functions supported except 3D color matrix metering, i-TTL balanced fill-fl ash for digital SLR
Non-CPU : Can be used in exposure mode M, but exposure meter does not function; electronic range finder can be used if maximum aperture is f/5.6 or faster
*1 IX Nikkor lenses can not be used
*2 Excluding lenses for F3AF
SOurce:
http://www.dpreview.com/reviews/nikond80/page2.asp