PDF annotation program

Hi, I'm looking for a PDF Annotation program (preferably freeware) that I can use to take notes in class. My Prof gives out PDF files for us to print and bring to class. For numerous reasons, I'd prefer to do this using my tablet and MBP. I've tried Jarnal, it is very slow and buggy due to it being a java applet. Are there any programs that someone can suggest to allow me to annotate my PDFs?

Thanks

 

Thanks for the tip, I'll give it a try. Although, if people have other suggestions, the more the merrier!