Basement Rental (Income, Legal, Recommendations, etc.)

[Jashan Mundi]

I'm curious about knowing the market for finishing and renting a basement to tenants.
I've targeted the Detroit, Buffalo, and Niagara falls markets for single and/or multi-family houses, but I'm interested to hear from any investor outside of these markets.

Here in Canada, it's quite common to rent the main floor and basement so an investor gets that double source of rental income. I'm not sure if the situation is any different over in the States.

1) What kind of rent can I expect with a finished basement?
2) Are there any legal restrictions and/or procedures that I should know about before finishing the basement?