Hi, Dotsie and Speakermom!
Yes, I do have an agent. I submitted queries to both agents and publishers simultaneously, deciding to go with whoever wanted me first! The publisher came through first, but by the time I'd had my second book published, I attracted an agent for movie rights, foreign rights, etc. The best way to attract an agent (in my opinion) is to use the Writer's Market books and carefully select people who work with your particular genre. Once you have one book published, it becomes a "numbers game"; the first thing another publisher or an agent will ask is, "how many books have you sold?"
Speakermom, good advice. I would never send a query or manuscript to one publisher at a time. It could take decades to find one at that rate. I sent out about 20 at a time, and highly recommend it!