I've posted a number of large panorama photos recently that you can zoom in on to examine in detail. For a simple blog post I thought it was worth mentioning how they are produced.
The zoomable images are produced and displayed using the free Zoomifyer EZ. You simply specify a photo and it produces a set of image titles and different zoom levels along with a configuration file specifying how they all fit together. The viewer is a simple Flash movie that can be embedded in any web page and customized (to some extent) to suit your needs.
All in all I think it is a great application (especially considering its free) that makes it easy and simple to add large photos to any website. Of course to really make use of it you need large images, in a future post I'll describe how I produce the large panoramas (i.e. stitch multiple photos together) that have appeared on this blog.