It is designed for DX (APS-C) sensors. While it fits FX mounts, it will produce significant vignetting unless used in 'DX Crop Mode' on full-frame bodies.
The lens uses a large 82mm front filter thread, ideal for high-quality ND or CPL filters.
Yes, it features an internal silent drive-module (SD-M) that allows it to autofocus on Nikon bodies that do not have internal AF motors, like the D3000 and D5000 series.