Yes, paypal for everything. I live in the US and one of the US companies I've worked for sends me checks, but everyone else uses paypal.
Here's ArtPACT's guidelines for rating companies' payscales, it should give you a pretty good idea: http://artpact.com/Articles/32/PACT-Pay ... for-Review
You may want to get a membership with them so you can see the reviews, though they are mostly depressing. People often say exactly how much each company pays for different work. There's a ton of work in the $50-200 range (i.e. kinda awful).
Don't start work until both parties have signed a contract and they tell you how they will pay. If they ignore questions about payment: drop them. They are just looking to screw you.
Don't be afraid to ask clients questions about the business stuff or whatever. They won't think you're an idiot, they'll probably be glad to clear up any misunderstandings.