There are many resources for new businesses in the State of Colorado and the Colorado Small Business Development Center provides a really nice guide for new businesses referenced the Colorado Small Business Resource Book.
The guidance provided includes information on Business Entry Options. An interactive survey that can assisting you in identifying what one should consider when moving forward with a new or existing business.
There are many considerations when determining the legal structure of your business. In determining a legal structure, you should consider both your present and future needs for operating your business. To avoid duplication of legal expenses, licensing and paperwork, analyze your various options and choose the business structure that will meet your long-term needs rather than choosing a business structure solely for its short-term convenience. While it is not a requirement, it may be valuable to consult an attorney.
There are a variety of Legal Structures that list both the Advantages/Disadvantages on the site.