A320 flight crew responds to a TCAS RA generated by a VFR aircraft during descent.

Narrative

We were on the PIGLT1 arrival into MCO; approaching Rfiki intersection; level at 11000 and 250 KTS. The Approach Controller gave us a clearance to descend to 9000. On TCAS we could see an aircraft at our one o'clock position and 500 FT below us. We were in the clear; however there were numerous cloud buildups around us; and we did not see this aircraft. As we started the descent; the Controller identified this traffic as VFR at 10;500. After about 15 seconds; the Controller gave us a vector to a heading of 110; which we immediately complied with. Just as the turn was initiated; we received a TCAS climb RA. The First Officer; who was flying; turned off the autopilot and began the TCAS directed climb. We continued in our turn to a 110 heading. I then told the Controller we had received a TCAS RA; and were in a climb. I believe we received the 'clear of conflict' at about 10;800. We then told the Controller we were clear of conflict and he recleared us to descend. The flight continued with no further incident. I believe that we followed our procedures accurately; and they indeed were very effective in responding to these circumstances.