I am creating a five year cash flow table in excel. Months from Jan 06 to Jan
10 will be along the top and long running construction projects will be
listed on the left hand side.

The variables associated with each project are

Cost
Commencement date
Duration in months

I would like the Cashflow to spread the cost (on a straight line basis) over
the duration, with the first months expenditure in line with the
commencement date for each project and update automatically when the
variables change each month.

Can anybody help me?