I know of no way to make this automatic, but here is a trick that may help.
The following commands assume a NIC from 3COM and a wireless adaptor from
Netgear just for example sake. You would have to use the proper name for
your hardware, which you can list by running ipconfig /all in a command
prompt.
This is actually based on a solution I came up with for a Win9X user for a
slightly different purpose, where it worked very well. I don't guarantee it
will work for your situation, but think it worth a try. You could try this
in a command window first, and if it works, put it in two batch files with
shortcuts on the desktop. (You could probably use /release all for the
first command instead, depending on your setup.)
I would appreciate it if you would advise whether it works for you.
rem Switch to Wireless
ipconfig /release 3COM* [NIC name for example sake]
ipconfig /renew Netgear* [Wireless adaptor name for example sake]
rem Switch to Wired
ipconfig /release Netgear* [Wireless adaptor name for example sake]
ipconfig /renew 3COM* [NIC name for example sake]
