MeLabs has adapters here (thanks to Bruce for finding this link in another thread):
http://store.melabs.com/prod/adapters/ICD210A.html

But then you have to get one of their ICD programmers to do the USB interfacing; that makes our USB U2 programmer obsolete. I don't know if this will work with MCS+, it only talks about MPLAB.

As far as I know, our USB U2 programmer doesn't do in-circuit debugging (couldn't find any reference last time I checked).

Robert

EDIT: I do remember reading of USB-serial adapters, just never looked them up.