http://www.nikonchat.com/nikon-nikkor-micro-lenses/

Does this lens fit my nikon d3000?
http://www.nikonusa.com/Find-Your-Nikon/Product/Camera-Lenses/2190/AF-S-DX-Micro-NIKKOR-85mm-f/3.5G-ED-VR.html
That is possibly the best macro lens for the D3000. Auto focus, vibration reduction, and because it is DX and not FX it saves you money and weight. Some gush about the joys of having no auto focus. If you are considering buying a non-AF-S lens for your D3000, then switch your current AF-S lenses to manual, and see if you like that better.
Nikon 105mm f2.8 Micro lens review