Timezone weirdness on dual boot machine

[David Scriven]

I'm running FC6 & Win XP on a dual boot machine - Intel Core 2 Duo, Intel 965 chipset

There a weird situation with the clock which shows up when I go from  FC6 to Win XP
and back. If the clock is correct in FC6 and you go to XP the clock is eight hours fast. 
If it is then corrected and you go back to FC6, it is eight hours slow. The zones are set 
correctly for both systems - Pacific Time zone = GMT-8, so my guess is that FC6 is not 
correctly interpreting the timezone info when reading the system clock.

Anybody else come across this? - Is there something that I should set (or check
whether it's been set)?