If you are thinking of full-time then the ideal is to get rented accomodation with other guys from your course - leases from as short a period of time as six months. Cheapest, and most fun way to do it. Means probably when you first get there you wont have that sorted.
In that scenario may I suggest lodging - a sheet available from OAT has a list of people in the local area - I would visit first though - some are lovely and others...well, not quite so!
Feel free to PM me if you want the contact details of someone I stayed with - very very well to do family in a gorgeous house 2 miles from the airport - £10 a night.
The other option while you meet people and decide who you want to live with is the B&Bs and oxfords on-site accomodation. Beware; OAT's accomodation only has practicality going for it - it is expensive, not very nice, cramped. noisy, and full of Algerian Air Force boys - lovely lads, but oh so noisy!
Hope that helps mate, and enjoy your time there - I certainly did!!
JP