Engine/Power loss while in idle with AC on

Well the headline says it all, but here is what happens.  Anytime i have the of the A/c functions on, basically anything but the vents, anytime i put the vehicle in park, every 30-60 seconds or so the engine sound and the the lights start to bog down like they are losin power, but then it comes right back up to normal idle speed, the in 30-60 seconds it does it again.  During the time it is doing this, i can also here a clicking sounds coming from underneath the hood, which i am assuming might be the compressor or something kicking on and off.  ANy ideas on what is causing this and what i might be able to do to correct it would be greatly appreciated.  Thanks in advance.
 
3/21/08-  its a 2001 explorer sport, v-6  90,0000 miles.  sorry for leaving this info out earlier

Any special reason you don't want to share the type/year/engine with us?

Sorry, my fault, forgot to post that.  Its  a 2001, explorer sport/ v-6.  I apologize, i guess that would help a bit