Below are files you may download. Choose either the first for Palm versions upto V3.3. and the second for later Palms however no guarantee can be given that versions later than V5 will work as Palm are changing their operating systems continuously. If you have used the software successful with later versions I would be very grateful for you feedback.
Problems do occur from time to time and here is the text from a helpful user (Heather)
"I have made the Cykey work reliably with the Treo! The solution was the software patch from http://www.palm.com/us/support/downloads/rawir.html
"RAW IR Software Update for Treo 650 Smartphones"
Last updated September 5, 2006
This software update is designed to resolve an issue with the transmittal of unpacketized data over the IR port on Treo 650 devices. Once installed, applications and accessories using unpacketized data, such as the Palm Universal Wireless Keyboard, will function correctly. Without the patch it can take between 2 and 24 key presses (at least that I counted) before the Treo responds with a character. They are the right characters when it does (I think, though I am slightly suspicious of the Treo's number shift)"