The changes are highlighted in order by sheet. So I do everything in sheet 1 first, then 2, 3, etc. By doing so, I only need to call out the zone because the sheet number is implied.
In other cases, I use 3-C2, where 3 is the sheet number and C2 is the zone. There have only been a few people that haven't intuitively understood what that callout means when reading it in context of the print. And when I say "sheet & zone" over the phone, that's all it takes.
When multi sheets are involved, there should be a table on the first sheet that indicates which sheet has which rev. It will not call out zones, only revs.
Chris
SolidWorks 06 5.1/PDMWorks 06
AutoCAD 06 ctopher's home (updated 10-27-06)
In the UK we just listed this on the 'amendment' (eco to most of you). Each sheet of a drawing had a separate section on the form so indicating 'sheet' wasn't an issue.
My current place in the US doesn't go into anywhere near this much detail most of the time.