I am so sorry to hear that..! Mainly in the middle of the summer..! I'll tell you what..that sound means a new compressor. But..............you have options

a.-Move to Alaska (You do not need the AC there)
b.-Repair the system. Here you have two more options
Buy a remanufactured compressor ($300), before replacing you need to do the right things first wheather you are staying with r-12 or 134a.
The problem with remanufactrured compressors is that they filled it with POE or PAG that are not miscible with r-12. So if staying with r-12 need to change the oil in the compressor for mineral oil. If changing to 134a there is a lot of things to change, so you'd better stay with r-12.

Fred, I am zoooooooooooooo cool now.. don't you feel envious..!

well, it looks like the a/c compressor is near to death now. it always made a hiss noise when engaging the clutch like "shhhhhhhhhhhhh" but yesterday i heard a terrible noise with the a/c off, i tought it was anything but the a/c ... a really weird noise. But when i turned the a/c on it stopped making that noise and went back to the hiss noise. plus a strong smell of somethin' burned. now my questions:
01) If the compressor lock up one day (soon) what's gonna happen ? (brake belt, have to tow the car??)

02) will it damage the system? should i replace it BEFORE it blows or lock up? (i wanna delay it ... financial problems :o)

03) considering that the a/c works 100% besides the compressor, what do i have to change and how much it cost ?
(like labor, a rebuilt compressor, r134 conversion, freon, what else ??)

thank you all !!