Percentages and Percentage totals across sheets

Excel 2003 - The AIM of my WORKBOOK.
A number of TASKS make up a project split into two types on a sheet = A PROJECT
A number of PROJECTS on different sheets = A PROGRAMME.
A front Summary sheet to summarise the percentage completed of each type of TASK on each Sheet and A total OVERALL PERCENTAGE completed of the whole PROGRAMME.

In the end of the row cells & percentage cells, sub totals and totals - conditional formatting to change colours at upto 49%, 50 - 99% and 100% completed (ie RAG)

I have a workbook with each sheet having rows of TASKS to complete within a PROJECT.
Each row has an end column which has a figure entered manually as a percentage of the task completed.
Each sheet is divided into two types of tasks for the PROJECTand each task type has a sub total percentage completed.
On the first sheet of the workbook I have all the other sheets named in rows and in two end columns of each row I want to reflect the two subtotal percentages from each sheet.
Also on the first sheet in the workbook, I want to then have a subtotal of each of the two types of activity and below that an overall total percentage of the whole PROGRAMME.

Whether to have the end of row cells on each sheet as percentages or numbers.
What are the formulas for the subtotals on each sheet adding up the columns.
What are the formulas for the sub totals cells of each sheet on the front Summary sheet.
What is the formula for the overall total percentage completed for the whole Programme.


I hope I have given all the information necessary for some very clever person to help me out. By the way I am under a time contraint ont his - told it is needed asap:-)