Zoom Effect?

Not sure if this is where I should be posting this question… but I’ve been seeing this zoom effect used a lot recently and I was wondering how it was done? I just saw it used again at http://www.agencynet.com/ in the beginning you zoom into the top office, and depending on what area you click, the site transitions you to that area with a cool looking zoom trick. Any ideas how this is done? I’d really like to learn it.