We have a very special holiday episode upcoming in December, and of course the past two seasons worth of narrative is available online. Very Soon Now we expect announcements regarding hard-copy collections of a lot of the content, and of course there is and will be swag. (Wait until you see the S3 limited edition shirt.)
There's a very handy fan page here, providing a suggested reading order (and recipes). And if you finish that, you can go to the character livejournals for interaction and backstory (and recipes), and the message board for community and speculation.