Its quite a simple fix, unscrew all the main base screws from the back including the small fan duct from the bottom left, you only need to leave the screws from the central section and the bottom right panel.
lift off the lid and put it out of the way, you should be able to grab your faulty belt from the bottom of the dryer now, slowy pull the back panel away from the drum, it will come off with a little tug. slip on your new belt going all the way round ensuring the belt is tucked over the motor at the bottom left, the most tricky part now is getting the drum back onto the back panel because the belt is trying to stop you, with a little push and shove and using someones help its fairly easy to get it back in and lined up, once the belt is on you will require someone to hold the panel tightly while you get screws into it.
Once the belt is on turn the drum manually, keep your eye on the old belt track and the motor, (you can see the motor from the bottom left corner where you removed the fan panel earlier) now just make sure the belt tracks around correctly if so put your lid back on and re-screw it back together, if it does not track correctly just keep manually turning it while pushing the old belt back into its tracks.
Good Luck.
Nick, September 2009