I was wondering how I'd be able to join

Go to http://www.MagicSYM.com and click on the How to Join page. Then just fill out the application.

Its certainly worth it! Best thing i'v done in the past!

The solo performer, or would be performer , needs to check their community to see if there is an Assembly of SAM or, SYM near you.
You will be welcomed and asked to come to a meeting. Application forms should be on hand to help you through the process.
If you are a working performer, go to your local public schools and visit the library and meet the librarian. If you have posters or business cards you can leave a few with the librarian. Every library has an arts and entertainment section in their card catalog listing books. The magic section gets more calls for than you might believe and when someone checks out one of these magic books, the librarian the librarian can give the kid a business card or poster.
Letting the librarian know that you tell your audiences about the Dewey Decimal System and that you support reading and give out the number 793.8, you will havecacfriend and ally. This worked for me where ever I taught or performed for thirty five years.
Ed Solomon