Pocket PC 2000 was created as a consumer focused subset of WinCE 3.0. Many people still referred to it as WinCE 3.0 because it is based on the same code. However, PocketPC has various consumer features added in as standard (Word / Excel / Windows Media / Windows Messenger etc.) that WinCE 3.0 does not contain.
Pocket PC 2002 was an update to PocketPC 2000 still based on the original code base.