Where is oil filter located on 2008 Pontiac g6 4-cylinder?

Take off the plastic accoustic engine cover ("ECOTEC" on it, and take off the oil filler cap first). It just pulls off once the oil cap is off. Then look down where the dipstick is, there is what looks like a PVC pipe drain plug for a sewer drain in your basement. That's the cap to the oil filter. You'll likely need to bend a wrench or go out and buy an appropriate crow's foot to get in there but removing that cover will reveal the paper cartridge. It's a dry sump so there shouldn't be any oil in there and the cartridge will be only a little damp.