Visual Studio 2012 Express for Desktop (or any other flavor) is distributed free of charge. It is not intended for businesses only. Go ahead and register it and use it.
Now as for what to enter, I try to be as truthful as possible on forms that ask questions that there isn't a good answer for. In general:
- Business Name: My name (or sometimes N/A)
- Business Address: My home address
- Employees: 1
- My role: Sole Employee