iOS (Jailbroken): There are plenty of offline readers for iPhone out there, but if you need a quick, one-click solution that's integrated right into the Safari browser, WebOffline does just that.
WebOffline can come in handy if you're about to head into a mobile phone dead spot and need to hold onto a couple of pages you're reading in Safari. Click the action button in Safari and then Save for Offline. The page will be available under Bookmarks > Saved Pages. It's not as feature rich as an offline reader like Readability, but it works in a pinch. You can find it in the Big Boss Repository.