Compaq now offers SDIO drivers for the iPAQ 3950/3955/3970/3975. This update is required to support SDIO peripherals like the Socket or Ambicom Bluetooth SDIO card or the Sandisk 802.11b WiFi SDIO Card.
They can be found here at:
http://www.cewindows.net/faqs/sdioupdates.htm
I wonder if they will work on the 1910...