I felt the same way when returning to academics after six years in the work force. In my case, I continued working full-time, so it was mainly a matter of time management, and staying organized. As Jenstallon wrote, once you get back into the flow of things, those "academic skills" come back to you. Actually, I think having some work experience before starting grad school is an advantage.
Good luck in your new program, and most of all: have fun!