First make sure its actually the oil oan and not the valve cover, oil filter, or oil sending unit leaking. If you do replace the gasket, get the one piece rubber job, get the block and pan really clean, and put the gasket on dry. I just went throught this, so if you have any questions let me know. btw, you have to pull the passenger side motor mount to get the oil pan off, and if its never been off before, it can be a real PIA to break it loose -- mine was practically welded to the block
make sure to torque the pan bolts to spec, and you might want to replace your rear seal while you are in there. Here are some links that may help: btw, the oil pan bolt specs are wrong in one of the articles (its not 10 ft pounds for either size bolt); I don't remember them right now, but if you need them I can get them out of my factory manual.