Welcome! As others have stated, you first need to determine if it's safe to ride a bike. There are plenty of people who have seizures once or twice in their lifetime and that's it (I think they refer to them as idiopathic seizures, meaning that there is no real cause). If you're talking about epilepsy, however, you definitely want to make sure that your doc can give you the ok to ride a bike. While it's not like driving a car, you can still cause an accident or hurt yourself just the same.

As for getting started with bike commuting, I always tell people to start with the basics - a bike, a helmet, and a decent bag to carry your stuff (a backpack can work just fine for the distance you're traveling). From that point, start experimenting a little bit at a time. There's no reason that you have to rush out and spend thousands of dollars on high-end equipment. If you have a decent local bike store (LBS) in your area, they should be able to direct you to these basics.

Get a bike that fits. The fit matters far more than the brand. Make sure you have the basics for commuting in the weather where you are. If it gets rainy there, a good water-proof jacket is a good investment.

Other than that, use this bike listserv as questions come up. Remember that the first few commutes will probably not be that fun. Experiment with different routes on the weekend and don't let yourself get discouraged. I promise you that bike commuting gets more fun the more you do it. Heck, you may decide after the year's up to stick with it! Good luck!!