Hi DFitz:

Tomatoes are day neutral plants, so no lighting cycle change is necessary. Studies have shown that tomatoes grown under artificial light do best with a 16 hour daylength. You may choose to add a fertilizer with a slightly higher Phosporous value once the fruits have begun to develop.

Which they won't do unless you hand pollinate the flowers as they appear. Simply tap them with your finger several times, firmly but not so firmly as to break the stem. You may also use an electric toothbrush or vibrator to accomplish this task.

You'll be able to tell when the flowers have pollinated as the small stem holding them will stiffen dramatically within a day or two of successful pollination.

Here's a good site about tomato care in general.

Here is a link that might be useful: TomatoGardening.com