Had an interesting issue as follows - I configured Windows Network Load Balancing (NLB) on my 2 SharePoint 2007 Web Front End Servers on Windows Server 2008 SP2 64Bit and then proceeded to assign IP addresses to my Main Portal Web Application and the MySite Web Application (both web apps are on port 80 so using IP addresses to distinguish them apart rather than host headers). The weird thing is that unlike Windows 2003 NLB in Windows 2008 your load balanced Virtual IP does not appear in the list of IP addresses you can bind to the web application. Looking around on various forums it seems that this is some kind of a bug on Server 2008. A workaround for now which I used is to manually type in the Load balanced IP address in IIS when selecting from a list of IP addresses to bind to the web application.
As you can see in the example below the 172.16.0.50 is my load balanced address but does not appear in the list of IP Addresses in the drop down list so I have typed it in manually and this works: