The seven versions of Windows PDA operating systems.

Windows PDAs certainly have changed since the days of Pocket PC 2000

(first saw this over at 1800PocketPC.Com)

Those versions are:

1. Pocket PC 2000
2. Pocket PC 2002
3. Windows Mobile 2003
4. Windows Mobile 5.0
5. Windows Mobile 6.0
6. Windows Mobile 6.1
7. Windows Mobile 6.5 aka Windows Phone.