I figured out i can use the 5v from the arduino board and powered my zigbee module (maxstrem Xbee) and it works fine if i connect it directly to my serial port. If i try connecting it through the ftdi chip on arduino(by taking of the atmega chip and connecting the rx and tx on pins 0 & 1) it doesnt respond at all... I tried using a prolific usb to serial converter and have the same results why is this? but the same module responds when connected directly to the serial port. 
cheers,
Pracas