Depends on how far you are willing to go. I've had wireless issues on a Ti PB 800 since 10.3.2 (wireless locks up the GUI, wired runs cool all day). I have been told that the Airport software released on the Panther disks is fine and has solved similar problems for some people.
This would be my first thought as the problem began after you installed in update to the OS. I have seen links in the Mac OS X forum here that points to docs about reverting software. I have not tried this, as I have no need for potential downtime at the moment if something critical should arise.