What is your favour free app for offline viewing of HTML and PDF?

I am looking for a simple solution to be used for several hundred students, most have an iPod Touch, and some have an iPhone. I want them to be able to download some HTML (or PDF) content when they are online, ... then be able to view it, including navigating links, when they are offline.

I have read a things about bookmarking data:URI, but it looks too complicated. I know there are some nice commercial apps, but unfortunately we need a free solution. I know some universities (Stanford) have custom apps for students to use. If you're an iPod app programmer and can share some for a bare bones app (that we could customize) to download, store, and offline-display HTML, that would be way cool.

Any recommendations or suggestions would be appreciated.