ok all, heres the solution. you'll need to pull the door panel off to access the insde of it. now while your looking in there, look towards the top. make sure the window is down. youll see some plastic blocks the glass sits against (guide blocks) what happens is these get dirty. if you look at your glass you may see a streak scratched in it from top to bottom if its been this way awhile (this is a reason to keep windows clean).simply unbolt the blockd, noting their exact location. scrub them really good with soap and water and dry. roll the window up so you can access the lower portion to clean it, when done roll back sown. install blocks, roll window up to make sure everything is still good, install door panel and your done.
if the blocks in bad shape, bodyshps and dealers parts dept can order then, they're not expensive.
hope that helps some out. while in there lube everything lightly...
It really is a painful sound. I especially hate when you go to a pay parking garage, and you have to roll down the window to get the ticket, then you put it back up and the squeak/squeal echoes in the garage- ack it hurts!