Kentucky itself does not require permits, license, test, fees etc to do low volt wiring but you do need a sales & use tax/general business license to operate as a business and to be exempt on purchases for resale as well as collect sales taxes. Most counties, cities and towns (with exception of some high brow developments) don't require it either. I did work for the contractor's licensing board in Bowling Green and asked him flat out what the requirements were and there were none, zilch.
Recommendation though even if there are none obvious - the National Electrical Code (2005 is the current version) done by the NFPA has regulations for low voltage, communications, etc that affect the entire United States. Get at least the section pertaining to low voltage and uise it as your guide. If you find later that a locality has their own laws they can only expand on the NEC, not lessen it as a lower government cannot preclude or reduce a higher government's ruling. Anyway with that said a quick trip on the web to your secretary of state's office might help as they are usually the licensing dept for your state to include electrician's licenses. I believe the general rule is that anything that has over 45 volts is considered requirement for an electrician's license. One thing to also note that even though there may be a local requirement for inspection, a homeowner is generally free to do his/her own work, within regulations and requirements. I have done all of my own service equipment, new and replacement wiring. Passed every time that an inspection was required. Care and patience are your best tools as well - always do a customer's job as good, if not better, than you would do your own job and do it for looks, functionality and safety - reputation will follow. I always put an installation label on the main interchange to both do a signature of sorts, and essentially leave a business card of sorts behind. I've gotten many return calls due to those labels on things I've repaired and cabling installations. I use a tyvek or plastic based label with laser printing and a permanent adhesive - keeps competitors and age from removing the stickers.