Australian mobile operator Optus is using the Web to explain its clients the "push to talk" service. A series of animation with an extremely nice graphics allow users to find out more about how it works in real life situation. A very simple competition invites people to submit ideas on how they could use "push to talk" in order to enter a draw and win a Nokia 5140. Online ads are used to drive traffic to the microsite.
Even if on the site there isn't much interactivity, I like the idea of using the Web to explain services. In this case the focus is on mobile, but we can take advantage of Flash animations to explain an enormous range of products and services. Integration is the key