I volunteered through the volunteer department. When you do so, make sure you get placed on a unit with patients and a nurse manager!! The nurse manager is the one who makes the hiring decisions (and who can push your resume through to HR) so you get hired. I would recommend volunteering consistently on the same unit so that you can become friendly with the nurse manager and staff.
At first, the volunteer department had me placed in a non-patient area of the hospital, but I made sure to get in a unit where I could meet the nurse manager.
And yes, they knew I was a new grad BSN/RN, and don't mind. They are hiring! Just get your foot in the door, impress them, and hopefully good things will happen! You know you're a great nurse, they just have to see it! Good luck!
(Feel free to ask me any questions. I've been looking for a job for so long, and I totally get how it feels!)