My 88 4x4 blazer has oil leaking from a hole under it .. somewhat hard to describe and if needed I can post a picture. It drips from the center of the car from a plate. It looks like there are 2 screw-holes on either side of it .. oil drips from the hole and seems to come out a lot quicker when running. Pretty car illiterate so help would be appreciated.

Do take a picture, then we may be able to help you out.

Sorry the picture is poor this is the best I could take from under the car.
http://thrul.homestead.com/files/hole.jpg

I would guess it is the Rear Main Seal leaking from the hole in the bottom of the tranny cover.

Just drove it about 16 miles and it looks from my oil check that it leaked 3 quarts of oil in that period of time. Assuming it is the main seal what is the estimated cost of replacement, and how difficult is the fix?

You've got a serious problem if it is leaking that much oil in that amount of time. Please take your truck to an experienced garage/mechanic for an estimate. If it is the Rear Main Seal, it is not a job for an inexperienced mechanic.

Yea i think you need to take off the oil pan and take out the oil pump, don't try that yourself. Load up on oil and get to a garage.

Checked the oil myself .. It didnt leak even close to that much my mom checked it incorrectly, will take it into the shop tho .. after research its lookin like its probaly the main seal.

My 88 4x4 blazer has oil leaking from a hole under it .. somewhat hard to describe and if needed I can post a picture. It drips from the center of the car from a plate. It looks like there are 2 screw-holes on either side of it .. oil drips from the hole and seems to come out a lot quicker when running. Pretty car illiterate so help would be appreciated.
the small hole u talking about is in the center of the dust cover and the oil leak is a rear main bearing oil seal leaking ive been mechanic for bout 14 years and have a 91 gmc 4.3 liter doing the same dealership here says 5 hundred to fix it seal is bout 8 bucks