Changes to Microsoft Licensing

I’m currently reviewing our current arrangements re Microsoft licensing, and I’m interested to know what other companies are doing about the software assurance changes they are implementing. We have 500 seats, and have recently upgraded our desktopsto W2K, though the servers are still NT. I reckon we won’t be changing the pc’s for at leasdt 3 years but the servers are more likely candidates. What’s anyone else doing out there????