Paul Cresham posted an elegant solution for this including working out holidays on the fly, albeit for the UK.  It did contain a nifty Easter algorithm, as well as tackling the @@DATEFIRST problem.  see

http://www.sqlservercentral.com/forums/shwmessage.aspx?forumid=23&messageid=110259

I documented it with an example of how we use it at

http://glossopian.co.uk/pmwiki.php?n=Main.WorkingDays

Dave Jackson