Need help forming a business

It has gotten to the point where authoring is no longer a hobby. I have money coming in and money going out and I need to do a better job of keeping track of everything. Now that I am advertising I have money going all over the place and when tax time comes, I'm going to be screwed if I don't get things in order.

I need help forming a business in Florida. I figured I would call it Katie Leone - author. I don't know if I am a corp, an llc, or what not. Anyone know what they are doing and can help, let me know. I need to get a separate bank account and other things as well to keep track of expenses. Luckily I am not so far behind where I don't know what's come in and gone out.

Please help.