I just became a member of Sports Shooter. After submitting your application which includes photographs and information about yourself, you have to be approved by the company in order to join. Though I don't know how rigorous the restrictions are you have to meet their standards to be able to become a member.
I had thought of becoming a member for quite sometime but never pursued it. Now that I'm in a new state I figured it could only help me get my name out more.
I recommend you check out some of the wonderful work on the website beyond my own page. There are some fantastic photographers on the website. I'd especiallly recommend looking at Jeff Adkins and Adam Cairns who are both photographers I know personally.