Listen to the post above having you check to see if the compressor clutch is engaged. That was the problem with mine. I removed a shim from it and it hasn't given me any problems since.

I had this same exact problem.. spent tons of money replacing stuff like the compressor, and then money to get it vacuumed and recharged, only to find out that wasn't the problem like they told me it was. Don't go through what I did...

It's the compressor relay!

+1 on the compressor relay! I had the same problem in my 92 EX.

When the AC stops running, pop the hood and look for the relays on the driver's side front, attached to the core support.
http://z.about.com/d/autorepair/1/0/j/C/57459321.gif

When the AC isn't working, try thumping that relay with your fingers. If you hear a loud CLICK (compressor clutch engaging) and suddenly your AC works, there's your diagnosis.

Be sure to replace BOTH the compressor clutch and condenser fan relays. If one is bad, the other isn't far behind. If you're at a standstill with the AC running and you have no condenser fan, your compressor could blow up.