Date Planner

Hello,

I am scratching my head on this one and not getting anywhere, so help needed!

I am constructing a date planner, with a list of jobs on another worksheet.
I would like the date on the job list to update the planner:

i.e. If the job in the worksheet was attended on date 13/07/07, I would like a green box to appear in the planner worksheet for that date, in the corresponding site row.

If anybody can help I will be very grateful,

Cheers,

James