I'm in the US (Georgia), and the first thing I did to limit liability is to form an LLC (simple overview: http://en.wikipedia.org/wiki/Limited_liability_company)
The process only took a few weeks from start to finish, which was a nice surprise.
Getting an EIN from IRS is free and took about 10 minutes.
Not sure about any local paperwork you'd need to file in NC - I didn't have to file any in Franklin county.