You didn't set a budget so the best is for you to contract it out and have it done.
Many others have a budget and use Ustream (.com). At that site is a FAQ and a page of supported gear. I can't duplicate all that here but you should look at it.
I am looking to set up a live stream feed of our youth group services and wanted to know what would be a good and simple set up for our classes. We have a PC, no fire wire port, and is a small venue. Thought about going with a webcam, but not sure what the best option is out there right now.