Are you a website developer/designer ? please answer

Hi,
"Where can I find an online or offline community of website developers like myself? I live in Los Angeles, CA." - try facebook groups. There are a lot of them there. (I personally like Freelance Web Design/Development Discussion group; it's a closed group but I highly recommend it. Also, once you join them, check their Files section. They have there a sample contract and agreements.)
"Where to find information on how to get started? For example, what questions to ask potential client, payment method, rates etc..." - I don't think there is 1 complete place for that but I will try to answer your question.
Here is a list of questions I ask for website development/design:
1) I ask to provide 2-3 sites of his competitor which he likes (that is important; this will give you an idea what this client likes)
2) ask for his favorite colors.
3) I always ask to supply content for a site.
4) Ask how many pages he needs.
5) I ask to supply all images he wants to use for a site. (perhaps he has his own logo)
6) You need to ask him if he wants other services like for example: some people need content management solutions (I charge something extra for those services) or if he needs for example business card design (also some extra money)
7) ask him if he has hosting/domain purchased. You will need all usernames/passwords eventually to make it live.
Couple of other advises:
1) never offer any free work (unless if it's 30 min work)
2) always ask for 50% deposit.
3) never offer unlimited revisions
I hope this is helps.

Stackoverflow and css-tricks have always helped me out. Not sure about a community though. Site Point perhaps?

I also think that nobody is going to offer their trade secrets to you for free. It's an insanely competitive market where everyone's looking out for number one.