From PocketPC Mag. (e-mail update):

If you read eBooks on your Pocket PC 2002, you are probably aware that MS Reader 2.0, the version of MS Reader that is installed in ROM on most Pocket PC 2002s, has, um, a slight memory leak. This can lead to a general slowdown of your device as you read a book. Large .lit files with lots of images—such as the Pocket PC magazine MS Reader edition—can make this slowdown happen in a hurry.

At long last, Microsoft has released an update to remedy this. You can download it for free here . If you have a Pocket PC 2002, download the full installation file. During the installation, respond Yes To All when prompted to choose whether to install new files.

If you have a Pocket PC 2000, you do not need this update. See the update page for instructions for determining whether your device is a 2000 or a 2002.