Get hold of a copy of the FAA exam CD by ASA.
If you dont have access to a PC at home then you want the red FAA exam book by Gleim.
You can also pick up a copy of the FAA Instrument handbook, I gothold of a copy in the US for about $12 but I think the 'Pilot Shop' in London does it as well.
For software I just used Rant 2000, have played with MS FS2000 for practice since which is pretty good.