Hi,
Programmer to Go, right - don't have a PK3 only the Pk2, to use the PGT on the PK2 microchip suggest you use a battery pack on the usb socket !
What I did was disconnect pin 6 of the PK2 Output connector, its only used to program eeprom.
I then connected the USB+5v input rail to pin 6, the idea is that you can feed the target circuit with the direct 500ma of power from the PCs USB port; the Pk2 circuit can only supply 100ma max.
This also allows the PK2 to feed off a target board, if you connect pin6 of the icsp socket on the target board to its own +5v.
Of course its not a good modification to make if you expect other people to use icsp on your boards.
It also has the problem that if you have the PK2 connected to the PCs USB and to a powered target board then something will probably go bang when the to +5Vs meet !!
Do not know if you can do a similar thing on the PK3 ?