Heavy oil leak solutions & advice

I drive a 1998 GMC C1500 5.7L V8. The body of the truck has around 240,000 miles on it.. but I had a 350 crate motor put in it approximately 4 years ago... which has (I'm guessing) around 70,000 miles or so on it.. I've had a small oil leak for a while, probably a year or more.. but it was so slow, I didn't take it seriously.. It's definitely not a slow leak anymore! It's leaking bad! I know that the leak is coming from directly above my (vertical) oil filter.. it runs down the filter & drips off.. Can someone help & guide me through changing the gasket from the oil filter housing to the block, & the oil filter adapter gaskets & seals.. I would greatly appreciate any help/advice!