Over at Xtranormal, someone has put together a short video on an introvert trying to find ways to participate in church. It's pretty hilarious, even if it's a bit stereotypical. Here's the link:
Introverts in the Church: Xtranormal
For the record, some introverts can make excellent greeters and youth workers, and we don't all need to be consigned to behind-the-scenes roles, though that may be a good starting point for some. Remember that 40% of megachurch pastors are introverts.