Compensation: There are exceptions to everything, but in general Junior Developers and Junior BA make about the same, Experienced Developer and Experienced BAs make about the same, Specialized High End Developers and Specialized High End BAs...the High End Developers make a bit more.

Entering the BA Market: It's always best to try and expand your role within your current company/organization.  Ask if you can take on some BA responsibilities in addition to you current ones.  Read everything you can about different BA skillsets.  Get the book knowledge under your belt.  And this leads into the third question about certs.  Some BA courses can be helpful, but they alone don't usually get you a BA job.  They just show that you are serious and that you have some foundational, theorectical knowledge.  True certifications aren't usually available without a minimal level of hands on work experience in the BA role.