Here are a few comments that may help do-it-yourselfers who want to change their timing belt - they would apply at least to the engines without variable valve timing.

I followed the Bay13 instructions - do the steps in the exact order listed. Look up the link called "Timing belt removal trick" on this site for an additional hint that worked for me.

On removing the belt I decided to replace the water pump, as its bearing was a little loose side-to-side but did not turn easily. I thought it might not last till the next scheduled timing belt change.

To get the water pump out (and the new one in) I needed to remove the tensioner idler and arm (and use the "Timing belt removal trick"). Otherwise I could see no free path to remove the pump. The idler arm pivot is held to the block with a T45 Torx bolt - you need a rather short Torx bit to get it out. Don't just take off the idler - take off the entire arm and pivot (and clean/grease them). If you just take off the idler and leave the arm it will be hard or impossible to retighten the idler on the arm because the idler bolt is not captive.

Also to replace the water pump you should drain the coolant from the block, not just the radiator (see Haynes manual or Bay13).

On Bay13 it suggests using a bungee cord to hold the timing belt under tension while installing and positioning it. This worked well with a strong bungee cord. The key point as they note is to keep the right traverse of the belt (from the crankshaft sprocket to the intake cam sprocket) tight. Otherwise it is easy for the belt to slip a tooth along the crankshaft sprocket while you are trying to position it correctly on the exhaust sprocket.

good luck...