You do realize that the software is activated by contacting Microsoft right? It's not like the old Win2K or 98/95 where all you needed was a code that 8 million other people were also using. It actually makes you go online and it hits their server before it will activate, it will give you 30 days to do this though.
Man, I have installed XP Pro hundreds of times and never had to get online to activate it. Matter of fact, it will ask during install if you want to register and I simply select no. All you need is a good key code.
yeah, and keep the internet connection unplugged until you're through with the install. Someone i know monitored the network traffic coming out of their computer during an install of windows and said there was tons of data being sent out