I and a lot of my friends have been getting emails recently that say "log into eBay or PayPal or whatever to confirm your password or whatever..." basically something that wants you to log in to their website to "confirm your information" or something. It only takes a simple mouseover of a URL to find out that the page is spoofed, but sometimes even that's not enough.
I haven't tried this plugin myself, but it sounds like a very smart idea if you've been getting suspicious emails like this and don't know what to do about it. It'll tell you straight off the bat whether the page you're on is real or not.
What's that, you don't use Firefox so this won't work? Ha ha ha ha ha ha ha ha ha.
On an unrelated note, blogging from bed is a pleasure I can't believe I've lived without up until now.