Entertainment Attorney Associations
First, please note that not all entertainment attorneys are created equal, and not all do all in the entertainment field.
Some specialize in making deals, others in confirming the language of a deal and your understanding of it before signing.
Others have expertise in providing contracts your company will need to monetize your creations as you deal with contractors such as sound engineers, studios, session singers, session musicians, and so forth.
Performing Rights Organizations (PROs)
These are joined when your business goals include tracking royalties through broadcast and performance methods such as radio, television, movies, plays, and concerts.
You will not want to join any PRO if you only have the thought that you might just maybe want to be in the music business, or if you've written very few songs. Joining or affiliating with a PRO is a business decision and these organizations will treat you as a business, even if the business entity is you the writer. Hold off on making a decision to join a PRO until it looks like you will want to stay in this business.
In other words, you might find you prefer writing and performing live, and even selling your own works on CD's you get manufactured then sell from your own website, and you will not have any outside broadcasts to track. If you're a hobbiest and this is a stress buster more than a full-blown business, don't worry about joining a PRO. Nothing wrong with that. Lots of people are hobbiest and have a great time entertaining and inspiring others with their music.
But if this is a business decision for you, please note you may only join or affiliate with one PRO as a writer, but can join all three as a publisher. SESAC does not charge a paperwork fee to affiliate, but they have a higher standard of affiliation that requires an interview wherein you will let them hear some of your work and discuss your business goals. BMI and ASCAP have paperwork fees, but these fees are not bank busters. All three have criteria you must meet before you can sign up. Click these links below to start getting that information.