Hi guys, I finished off the job yesterday, and all seems to be working fine.
I followed the guide that Kev Watkins posted, and I also used an online tech spec workshop manual, both of which were invaluable to me for the duration of the job.
http://bahamutcars.com/workshop/IS_98-05/contents/index.html
Above is the web address to the tech manual.
Overall I replaced the timing belt, tensioner, idler, ac belt, ps/water pump belt, alternator belt, water pump, spark plugs, air filter, coolant, oil filter, and oil.
The parts totalled at £390, which in itself is a fair amount of money, but I reckon that I have probably saved myself upwards of £400 by doing the job myself.
For anyone out there thinking of changing their belts and pump and are a little apprehensive, take a couple of brave pills and follow the guide posted by Kev, take your time, work methodically, and I'm sure you will be fine.
A good quality socket set, a torque wrench, a little patience and an abundance of brave pills should see you through to the end.
Thanks to the posters on this forum who replied so quickly to my earlier questions, and here's looking to the next 60000 miles in my is200. ;)