I wanted to make a note of a solution I found today in the hopes that it will be helpful to others and easier to find.

Until today, hot-syncing my Sony Clie PEG-SJ22 with my Dell Inspiron laptop was so slow as to be useless (more than 20 minutes before I gave up and cancelled the operation). I finally was able to track down a fix via a lot of googling and came up with the following.

The problem is the with the SMC IR driver used by default in WinXP. Apparently, it tries to communicate much faster than the Clie can handle. Throttling it back via the driver controls doesn't fix it. The trick is to replace the SMC driver with the generic Windows IR driver. This means the following:

1. Go to Control Panel -> Wirelss Link -> Hardware tab -> Properties for the IR device -> Driver tab
2. Click Update Driver...
3. Install from specific location. Next.
4. Don't Search. I will choose the driver to install.
5. Uncheck Show Compatible Hardware
   
6. Choose Manufacturer (Standard Infrared Port)
7. Device: Built-in Infrared Device

That's it. Reboot and everything should be groovy. Of course, groovy means a poky transfer speed of 115Kbps, so even a useless hotsync (right after a complete hotsync) takes 1-2 minutes. But that's useable if you don't have a USB cable handy.