Internet Marketing Va

Business licenses in other states to do business online?
I am currently in the process from a store Online Internet. My company is registered in VA, but I intend to market to all 50 states. Do I need a license to do business elsewhere? Will I be subject to tax in VA? Thank you.
The http://homebizseo.com/50states/50statehome.html listing, state by state to start a business providing links to government Web sites each State manages the process of starting a company.
Internet Marketing VA
