We just started a BCA league last fall. Call their office and they will be very helpful.
For APA, contact the League Operator listed on the website for your area. Look at all of the requirements for both carefully before you decide. As you have probably seen on this forum, there are pros and cons to both. BCA gives you more freedom to set your league up to suit your poolhall.
Hope this helps.
You should also look into starting a league with the USAPL. which has been set up to compete with the APA. They are a fairly new product from CueSports International, the parent of the BCA. Sounded like a fairly good deal for players with Fargorate hot races, payback for winnings and lots of chances for trips to Vegas where they share the venue with the BCA Championships. This is according to the aspiring league operator who explained it to me while trying to recruit captains.
Start your own league.
Even if you buy a franchise.
These league operators will end up holding you hostage if you let them in.
You'll be getting 3 bucks a player and they'll be asking for tap water while eating pbj's from home.