Welcome to the Shadows! I hope you'll enjoy the site. There are several active games, some of which may be willing to accept applicants. If you want to join up on any, just let the GM's know that you're interested, and work out the characters with them.
As for GMing, there can be problems with relative "newbies" being GM in games, but most of the players on this site are more than willing to work with the GM to smooth out the rough spots. Also, we have an active Admin (myself) and an active Moderator (wngd_phantom) who are both more than willing to drop some advice from time to time.
That said, gaining some perspective is always a good thing when it comes to being GM, and the best way to do that is by playing! So, enjoy your time on here.