i did the timing belt on my girlfriends stag on the weekend, had it done and dusted in about 2 hours.
few tips, when you take the radiator out, as the remove the transmission fluid hoses from the bottom, you can quickly plug them up with 2 bolts (something about 8-10mm thick should be fine) so you dont lose any fluid.. although, if your fluid hasn't been done in a while, it might be a good idea to drain that first.
taking off the harmonic balancer without a rattle gun is possible... there are 2 ways i've used.
first method is using a breaker bar, and a gimpy.. you can give it a few sharp hits and hopefully crack the bolt,
or the second way is by using a length of rope (about a metre is all you need), you put the double loop over the balancer, and then tie the bare ends up to something such as the water pump, you need to make sure you have the rope around the balancer the right way though, you want it so as you try turn the bolt anti-clockwise, the rope will pull back on itself to the point where the bolt comes loose.
here's a pic of how the rope should be looped, as i had no idea how to explain in!
when fitting the belt, it's best if you have someone helping you.
remove the old belt, and the idler/tensioner pulley, then put in the new idler and tensioner, then line up the 2 top marks on the new belt with the cam gear marks, at this point only have the belt about 2-3mm on, and get the other person to hold the belt on the gears, and the tensioner AWAY from the belt.
go under the car and slide the belt onto the crank gear (makes it easier to see the markings from under the car, then come back up, and then slide the belt fully on, and release the tensioner onto the belt.. and voila, you basically just have to put everything back on after that.