Next to having a proper business license you should also think about things like liability. What if somebody sues you for lost revenue due to an outage. Due you want to be liable with your personal assetts? Probably not. I am running my business as a LLC (Limited Liability Company) to protect me and it also looks more professional. A corporation might be another option for you. Depending on where you live you will also need a sales tax license.
Go to
http://www.nolo.com and read up on these things. They offer generic, but solid information.
Chris