All the past papers are in the short loans section in the library (floor 0, at the back next to the check out desk thing). All the papers are in boxes according to subject, and grouped into years, so for example all the chemistry papers for 2004, for all levels (ie 1st to 4th year) and bound together into a booklet in course code order (if that makes sense). To get copies you have to put some money onto your campus card and then photocopy the papers relevant to you on the machines in the short loan section. You can't take the booklets away with you, and the answers aren't provided. However some of my papers have been posted on blackboard this year, which saves me the hassle of going to get them, and also the photocopying costs! Its worth photocopying a few years worth of papers to have a practise with, so that you get used to the format and timings and stuff. Having said that, I still haven't attempted any of my past papers yet these holidays!