The PL2303 is a really lousy chip, I wouldn't waste any time on it.
pcfr33k:
it has a Vcc reading 3 volts and another Vcc that reads 5 volts.
Without a schematic, it is going to be tough to solve this strange puzzle. Since it doesn't look like there is a regulator onboard, it could be that the 3V3 isn't VCC, but a regulated output from the PL2303.