Will the Sigma 30mm 1.4 autofocus on my Nikon d3000?

And If you happen to have it or know about it… Would you consider it a good lens choice for my camera?

It's full name is 30mm F1.4 EX DC HSM That HSM is the key, that's sigma's equivelant of AF-S so yes it would work. I can tell you didn't look at the sigma site otherwise you would have noticed * Nikon Mount: Built in motor lens: compatible with D40, D40x, D60, D3000, D5000

If you like 30mm it's a fine lens.

Yes, it will autofocus. It's a good lens depending on what you want to take pictures of.

You may also want to consider getting the Nikkor 35mm f/1.8, which also autofocuses and is optically superior to the Sigma.

Yes its a good lens

Sigma 30mm f/1.4 EX DC HSM Lens for Nikon Digital SLR Cameras

Designed to fit Nikon digital SLR cameras
30 mm focal length
2 low-dispersion glass elements; glass mold aspherical lens element
45-degree angle of view
15.7-inch minimum focusing distance