Take Care and get professional advice. For short term rentals you would be ok I think BUT if you are offering a service that could be classified as a Rental List then the penalties for getting it wrong are huge. "Rental companies or anyone who advertises rental property information or lists in any manner is acting as a broker or broker's representative and is subject to the laws regulating licensed occupations" (Florida Real Estate Principles, Practices and Law – Crawford).

The Florida Statute 475 covers this in full and is available at http://www.myflorida.com.

Its a first degree misdemeanour and the maximum penalty for this is a fine of $1000 and/or imprisonment of up to one year! Of course if you're doing this without a license then all the penalties for that would also apply.

On a more practical side, there are hundreds of sites offering this service for very little money as well as thousands of individual sites offering vacation rentals – are you sure this is a good idea in an extremely competitive business?

Not to pour water on you fire but I'd look very carefully at your business model and wish you every success.