UPDATE July 29, 2011: Google seems to have disabled this feature (a few months after it came out, actually). In any case, I find locally-installed extensions such as Firefox SiteDelta to be more reliable than online tools for this task, as you control the verification schedule (e.g. I tried Page2RSS, but never got any updates in the provided feed).
Just a quick post to underline a Google Reader feature which, though simple, may come in handy: creating a feed for “feed-less” sites. It basically tracks updates on pages by periodically checking the pages you choose. I need to mention that for table-based pages (or any page with recurring pattern but no feed) there are existing services such as Dapper which will allow you to create a more sophisticated and precise feed by creating a page scrapper on-the-fly. It’s the kind of feature for which I tend to find more and more uses as time goes on. One significant example I’m thinking of is personal homepages of friends and people who haven’t yet integrated a feed: it’d be nice to be alerted when they change.
(Via this LifeHacker article)
Update the next day: there seems to be plenty other similar services. ChangeDetection.com is an old one, sending updates via email. For others, just Google for “monitor page changes”.
(To be perfectly honest, from a programmer’s point of view, I guess you could do the same by having a list of URLs and setting up a script to periodically check whether significant changes have been made (i.e. using a “diff”). Yet I never took the time to do it, and now that’s it’s easily available…)