What's the difference between a nikon d3000 body vs nikon d3000 kits?

Is Nikon d3000 a good camera?

The d3000 is a good camera, 1 generation back from the current model in the line.

kits include at least one lens, and possibly other items. Depends on where you get the kit, and what sort of sale they are running.

The "kit" includes a lens

While the D3000 is a fine camera, the D3100 is its replacement camera and may well be worth the little extra money