AvantGo is a program that mirrors HTML content on a variety of
handheld OperatingSystems (PalmOs, PocketPc, etc.).
A public and free AvantGo server can be found at http://www.avantgo.com.
This server provides a number of news and information 'channels' that
you can subscribe to, plus the ability to create your own 'custom channels', which can be any URL that you want to transfer to your handheld device.
The service is regrettably subject to some limitations because it functions by storing all the pages on the central server, then doling them out to clients as they synchronize (although that does keep the client software small and allow for centralized processing). Most notably, there is a size limit on what the free server will allow you to sync to.
ApplicationsAvantGo is a very powerful tool if used in the right way. With some modifications, you could theoretically synchronize a wiki to your PalmPilot and even edit the pages offline. The greatest disadvantage you have to deal with is the missing business logic behind the offline pages. Maybe it can be replaced by special scripting, but the capabilities of AvantGo aren't well documented for the non-paying users.