1. timing belt
2. Interference engine
3. AC Delco is OEM. Gates and Dayco are also good aftermarket alternatives.
4. I never had a belt snapped on me. Premature wear can occur for many reasons though.
5. Ive "replaced" a timing belt as part of replacing a head cylinder gasket. By itself, you have to have a bit of experience and knowledge working around cars. I am not a mechanic myself, but I've been doing almost all basic maintenance service on my cars for the past 10 years. My brother is a mechanic though, and If i need a special tool I dont have or dont want to buy myself, I have him bring it home on a weekend so I can use it.
At a minimum, you will need to jack the car up and place on jack-stands, have to jack up the engine and support it because youll have to temporarily remove the engine mount. Youll also need a basic socket set, an allen head socket set, a water pump socket tool, cam-lock tool, torque wrench, and probably a few other things im missing.
If your doubting yourself, just bring it to a shop. Especially on a job as crucial as a timing belt. If you mess it up completely, you destroyed your valves at a minimum, and break a piston and trash the whole engine at worst. If realize half-way though that you cant do it yourself, you're paying to tow it to a shop so that they can fix it.
Alldata shows replacing the timing belt as a 1.6 hour job on my 2004 Aveo. You can get a timing belt kit for around $120. Around me, the going labor rate at a shop is about $120/hr. Total price should be around $300-350 if you were to take it to a shop.