I am pretty sure my O2 sensor is shot on my 2000 Z24. The check engine light came on and I had a friend check the code and he said it was almost certain it was that sensor but then I heard there might be two of them...

and also, if I disconnect the battery for a while the light still stays on. If I leave it disconected over night should it go off or do I have to absolutely get ass raped by the dealer?

One in the exhaust manifold and the other is right behind the cat.

Danm that sucks.. I found a new O2 sensor for my car on Ebay for $60 but now my odds are even worse if there are two sensors.

OBD II

ok your gonna make me ask aren't you? what is OBD II?

on my 2000 cavalier i paid like 80 for one and 65 for the other brand new. call around a little

Danm that sucks.. I found a new O2 sensor for my car on Ebay for $60 but now my odds are even worse if there are two sensors.
i wouldnt worry about goin to ebay for o2 sensors. sensor1 usually sells for around 20 bucks,and sensor 2 for around $100 at any part stores(autozone etc.). obd 2=on board diagnostics 2;its in cars 1996 and up,the obd 2 trouble codes are the easiest to read on a scanner,the scanner tells exactly-word-for-word the trouble code... so,when you say that it "should be the o2 sensor" that code should of told you an exact pin point of which sensor on the scanner.... if you post the code on here i could tell you which sensor it is.(i.e. the code starts with PO)...