...they come back? I grew mint, basil and rosemary on my window sill for the first time this summer. What can I expect to happen to them as the weather turns? Will they come back next summer? Do I have to do anything to the plants or soil to make this happen?

On your window sill? Does that mean that they are in pots or planters that can be moved inside?

I suggest using a "cold frame" inside for the winter. I have a two tiered cold frame for use indoors which features 4 hanging fluorescent lights (2 tubes each, 2 lights per tier) in which I use the fluorescent grow light tubes. I put the whole unit on a timer and subject my plants to the typical summer "sun" of 16 hours daily. My portable outdoor plants continue to grow and thrive all winter long.

Here's an example of a cold frame, similar to what I'm talking about: http://www.greenhousecatalog.com/images/grow-light-tan.JPG