Adding days by using NETWORKDAYS 2007 formula

[tiger7ail]

Hello There - I need some help here. I did search the entire forum and seems like no one has posted this question before.

Background
==========
Approval received date: 31-Dec-2010
Work should start within 2 working days

So i need to find the formula that can give me the result of 31-Dec-2010 + 2 working days =
4-Jan-2011 (minus weekends)

I tried to use the NETWORKDAYS formula but no luck.

Thanks,
Mazu