I found info re: AW's beta program
here. It takes longer to start testing than it did when I started, but you can still do it.
You have to be over 18 years of age to test.
You have to sign an NDA agreeing that you will not share any information about beta projects. Everything has to be kept secret.
You should be able to find a link to the NDA on the boards. If you can't, you can just email Kieren (Kieren@astraware.com) and let him know you need a copy of the NDA.
One thing to remember is that the betas may not be particularly stable - that's why they are called betas ;). Frequent backups are a must because anything can happen. But I really haven't had any major problems.