Hi Andrew,
There is a system out there that prints a bar code onto your jobsheet, then the techs clock on and off the jobsheet using a "scanner" similar to the ones they use in shops, in addition to that, you can have "codes" for "waiting for parts" etc so you can see exactly how long each tech spends actually "working" on it.
Haven't got company details to hand but sure i could find em if you need it.
Actually we used to have similar system in Rover dealer years ago.

Regards
Dave