need help creating a timesheet to track one employee over different jobs

I am working on a "time sheet" the way it is configured now is there is a sheet called jobs. this sheet has 3 columns (job #, Cust, Job). Then I have a sheet for each week of the year. these sheets have columns (date, job#, cust, job, operation, start time, end time, total time, and paid).
What I am trying to figure out is how to create a formula in the jobs sheet to total hours spent on each job over the life of the job. There will be a new sheet added each week.

Thanks for the help.

I have attached a sample of the file for evaluation. I am using 2003 or 2007 which ever would work better.