Best it to use a Arduino Mega if you need both xBee and SSC32. Also do not connect any of them on UART0, so you can program your board without any problems.
If you want to use both with Arduino Uno or Diecimila, I advise you to connect the SSC32 to UART (115200 baud) and xBee to some other pins and use NewSoftSerial (9600 baud or more, to be determined what works best). You will need to unplug the SSC32 (or use a switch) when you program your Arduino board or you will get an error.
I just got my SSC32 yesterday. RoBotX, if you don't mind, could you show me how you wire up SSC32 with mega or uno and some simple code how to control servo? I really need help on this one. Thanks a lot~