Total hours b/w two m/d/yy h:mm stamps?

[chabuca1]

Hello, does anyone know the excel formula if I want to calculate the total working hours between two date and time stamps like so:

3/8/02 1:00
3/9/02 15:00
start work at 9:00
end work at 17:00

Result: 6.00 hrs (total "active" working time)

Thank you for any direction!