Found this interesting technique for adding preview images to your links, I had a play with it and found it to be fairly effective. Interestingly it does capture flash movies, which quite surprised me, unfortunately it doesn't capture PNGs which makes a few of my site designs look a little weird in the previews as banners, logos and other key elements disappear. I also couldn't persuade it to preview a page in a subdirectory, I always get the site root page.

It could be that this is just a limitation of not paying for it (we're basically using the service for MSN search above, I couldn't find any information about whether I was supposed to be allowed to or not), but I filled in an info request on the developer's website and haven't yet received a response so I can't be sure.