An easy way to keep current on instructor notes and homework question & answer is to subscribe to the following RSS feeds:
To subscribe in Firefox, simply click on the link, and save as a "live bookmark" (preferably in your Bookmarks Toolbar). To subscribe in Internet Explorer, click on the link and select "Subscribe to this feed…" You can view these feeds by pressing Ctrl+Shft+J.
There are many other ways to subscribe to a feed, such as Google Reader, iGoogle, and facebook. For more information about RSS feeds, see Wikipedia's article on web feeds.