Just to add to our confusion, D-Link modifies the hardware in their products to meet their price/availability needs, but without changing the model names.
I happen to have a DWL-650 Rev. P. This is a new, 16-bit card, based on the Prism3, and is the 5th ... that's right, 5th completely different version of the DWL-650. That doesn't include the 32-bit Cardbus version(s), called 650+, or any of the G versions either.
Luckily the Rev P seems to work fine with NS 0.3.30 in NDIS 5.1 mode with W2K.