While
palmOne has said that it was 'eventually' planning to release a driver for Wi-Fi card use in the Treo 650, one industrious owner already has solved the problem, and
Engadget posted the details.
Download the file and read the installation instructions
here. In 6 easy steps you should be swingin with Wi-Fi.
Note: This is not officially supported by palmOne, which may void your warranty or service agreement, so proceed at your own risk. < / buzzkill>