I was in a similar position where I needed to learn CAD for a new job. A few companies like solidworks have 30 day trials and those are pretty helpful. Most of the trials also come with tutiorials to walk you through a design. I have used Inventor, Solidworks, ProE and a few others in recent years. From what I have found, if you can work one CAD program proficiently then you can pick up any of the others fairly quickly. Obviously a few details change, but the concept of all of the programs stays the same and in recent years they have all started competing closely with eachother on the user interfaces.
and as far as p2p goes (and it is probably wrong for me to say it), if you are going to download large files, use bittorrent. I had more than a few classmates who got working, virus free versions of their programs so they could work at home. However, if you can afford the student version then that is the guaranteed way to go...