http://www.nikonchat.com/af-nikkor-20mm-f-2-8d-2/

Lenses for a nikon d3000?
Hey, I have a Nikon D3000 and I’m looking for a wide angle lense. I found the AF Nikkor 20mm f/2.8D on the Nikon site but I’m not sure if it would be compatible with my D3000.
thanks (:
The 20mm f/2.8 isn’t a good idea, since it lacks the AF-S feature and thus won’t autofocus on the D3000. It also isn’t that wide on a D3000. Your kit lens will go wider.
The Nikon 12-24 and 10-24 are some good lenses to consider.
Also, consider third party lenses like the Sigma 10-20 and the Tokina 11-16. I have a friend that uses the former and seems to be pretty happy with it.
W clouds