Want to Calculate business hours

hi Everyone,
I have one query, i want to calculate the business working hours (like from monday to friday 9 to 5 pm and saturday 9 to 2 pm) for the given dates. And also i want to eliminate the public holidays with in the given dates.
If any one was faced the same situation plz help me.

Regards
Venki

I want the table structure for the Holidays table. And also please mention where i have to store business hours (like 9 am to 5 pm except holidays).
If any one know please help me in this regard.
Thanks in advance
Awaiting for your reply
Venki