I am sure this is old news for people who know MS licensing, but I had no idea.
If you are a big user you can get continued XP support for a price: $200 per install per year with a ceiling of $250,000:
[
telegraph.co.uk ]
The British government (as always, the biggest suckers in IT purchasing) paid £5.5m just before MS announced the ceiling [
telegraph.co.uk ]