I've recently started using Photosynth, which is an application by Microsoft whereby you can create a "cinematic" effect with your flat photos.
The process itself is quite simple - you take lots of photos from all angles of the desired object, landscape etc and then upload them to Photosynth, which sorts them out and creates the 3D image. However, it does take quite a bit of practice to get the right photos and make sure you've covered all the angles. There is a useful tutorial video on the site, but I've found you need to spend time practising.
You can take a look at one of my first efforts on my other blog Corfu Chronicles, where I've posted a view of a Corfu landscape.
Can Photosynth enhance your blog? Well, I think it could be useful to certain types of blogs - nature, travel, art etc - and could perhaps generate more interest in a post than an ordinary flat photo would, but I think it needs to be done sparingly to be more effective. And I'm not sure that I like the Photosynth frame that the image appears in on the post.
The thing is that you need to spend time on it and take a lot of photos. Anything less than about 40 or so (depending on the 'size' of what you're photographing) is really not going to produce a 'synthy' image, as they call it. For the one I did on Corfu Chronicles, I took 115 photos!
So I don't think it's really what you would call a 'blogging tool', though I think that it can enhance certain types of blogs and posts as long as you don't overdo it.
It's fun though!