[Mark Nord]

Originally Posted by chris_tribble

The next question is going to be how to re-set time zone etc when travelling. At the moment the Reader gives me the correct UK local time (picking this up from the computer?). But I'd have no idea of how to change if this was needed.

I could simply say RTFM!
But I suggest you have a look on pages 88ff of the PRS650.PDF manual, how to set Date and Time, even with a not russified firmware.

Spoiler:

Settings
88
Table of Contents Index
Changing Settings
Tap [Settings] tab at [Home] menu.
[General Settings] ( 90)
[Date and Time]
[Date and Time Format]
[Page Turn Preference]
[Menu Language]
[Keyboard]
[Screen Orientation]
[Application Preferences] (> 91)
[Dictionary]
[Slideshow]
[System Management] (> 92)
[Power Management]
[Device Lock]
[Standby Screen]
[General Settings] menu items
[Date and Time]
Tap a field to change.
Input a number by tapping the numeric key pad.
Tap [OK] to apply the change.
Tip
The date and time of your Reader will be automatically
synchronized to your computer by the Reader Library after
connection.
[Date and Time Format]
Tap [Month-Day-Year] or [Day-Month-Year] to select
the date format.
Tap [12 hour] or [24 hour] to select the time format.
Tap [OK] to apply the changes

For the hacks just go to the about screen and use the buttons, the options should just toggle thru.