How to find out if you have an arrest warrant?

I believe I may have a warrant for my arrest. Is there a way to check on this, and to find out what the warrant is for? I called Warrant Services Division, and they told me to come in and bring ID. If I do that, I know that I would be arrested on the spot. I'd like to find out a little more information about the warrant to prepare for bail, before I do that. I live in the city of Oakland. I thought maybe someone here could help provide me with information.