It'll be non-existant tomorrow as well- at least for your 2125.  Phones,
like the 2125, are generally USB client devices, not hosts, therefore
they're designed to be plugged into host devices like PCs, not "receive"
peripherals into them.  The presence of a USB port on a device doesn't
mean it has full USB support- i.e. you wouldn't expect to plug a USB Wi-
Fi dongle into a USB flash Card reader and magically create a wi-fi card
reader!  The 2125's USB port doesn't support Wi-Fi either.  

Any phone would have to be specially designed to accept a Wi-fi dongle,
and have drivers to run it.  Seems to me that any manufacturer interested
in doing that would just build Wi-Fi into the phone in the first place.

Face it, Edward, you need to buy a new phone to get Wi-Fi!
T-Mobile's SDA is essentially the Wi-Fi equipped Version of your 2125,
and can be unlocked to work on Cingular, or Cingular's own 8125 and 8525
are Wi-Fi equipped already.