|There is no easy way to accomplish what yo want before Excel 2010.|
Excel 2010 has a NETWORKDAYS.INT() which does exactly what you want.
The best work around for those of use who are still on 2007 is probably this VBA code:
It is implemented as a UDF (User Defined Function)
Here is an excerpt from the instructions:
This function can be used as a replacement for the NETWORKDAYS worksheet
function. With NETWORKDAYS, the excluded days of week are hard coded
as Saturday and Sunday. You cannot exlcude other days of the week. This
function allows you to exclude any number of days of the week (with the
exception of excluding all days of week), from 0 to 6 days.
Take a look and if you intend to implement it, then let
us know and we can show you how to get the number of hours
in conjunction with the UDF.