I just found this page. Scroll down to point #9
links are included on that page for "remote extender" and "opie-remote".
EDIT: opps, the remote extender has been discontinued, but opie-remote should work if you are close to your TV set or IR receiving device.http://quickening.zapto.org/Zaurus.html
9. Altho the Zaurus has an IR port it is too weak for remote control. No problem! I bought the Remote Extender from smarthome.com. With it, I can use my Zaurus as a universal remote control from anywhere in my house. I used Thomas Steven's opie-remote software and configured support for my reciever, tv, vcr, tivo, and the hdtv, dvd, winamp, realone, media player, and browser on my HTPC
I have a Palm Zire 72, which works very well with an aftermarket remote control software, so I haven't tried opie-remote on my Zaurii.