A broad range of freelance opportunities and probably the most popular site. You can sign up for free and receive job notifications, but before you can bid on a job, you must pay to become a member.  Elance attracts a world-wide audience and so you will be competing against workers and companies from other countries.  Some jobs will specify US only or English speaking only, others will not.  Safe pay through escrow account.  Can browse jobs for free but many of the bids are sealed so its hard to tell what the going rate is.