SlideFlickr.com is, well, they give you embed-friendly Flickr slideshows that work on MySpace - all the Flickr stuff requires JavaScript, so you never see the official Flickr stuff on flash only sites. If Yahoo is smart, they'll get 'em summa this!

I am a fan of the "blog this" button, but again, no MySpace support, but that's not their fault. Honestly, I hate MySpace, but it is too useful right now.