If you are planning to do it seriously--I'd contact your local Small Business Development Center to see if they can get you some help on the general legal work--what I mean is making sure you have your ducks in a row so people, when buying them, are not buying the rights too or buying exclusivity.
I am all for small business and wish you luck dude--just remember it is a lot of back-work on that stuff and, before making a sale, make sure you have yourself protected!
Also, with game dev gear, I don't know if anyone caught this but you can now use Unity 3D (http://www.unity3D.com
) and Unreal 3 (http://www.udk.com
) for free as an indy (UDK can't be used commercially but you can upgrade to a commercial license if need be and, on top of that, if you want to make a tech demo to pitch for funding you can use it to that end)--so that is a really nice thing right there--I know on our end (Team KAIZEN) it has been a god send--we are debating ATM between Unity 3D or UE3 and will make a final decision tomorrow!