iPlayer from the BBC. I'd heard of this, but ignored the announcement once they'd said it wasn't running on Macs yet. However I recorded 'Ballet Shoes' while I was away and missed the end so I checked out the site to see if it was there, thinking I could catch it on my work computer. And I find that although you need Windows for the download, it's just Flash player for the small screen version which is perfect to watch on a laptop. It worked fine on Firefox, and I think I'll use it a lot now to catch things I've missed - or just to watch at a more convenient time.
iTunes U which has lectures and other presentations from American Universities online. The one that particularly caught my eye was 'Social Entrepreneurship' from Stanford University which includes a couple of talks by Muhammad Yunus, the founder of the Grameen Bank. If I get hooked on this, I may have to buy an iPod!