Microsoft LiveLabs just announced the release of Seadragon.com, an Azure-based service that creates hosted DeepZoom images 'on demand', making it super-easy to share very-high-resolution images with a quick link.
I tried it out with a few images from my Flickr account (they only take a minute or two to 'process')... click the links to play with Seadragon, click the images just to see a larger copy
Sydney skyline 9774 x 2154 (21 megapixels)
Seattle suburbs from the Space Needle 11991 x 2186 (26 megapixels)
Here's a few more to try for yourself:
Sydney at night 2048 x 768 (1.6 megapixels)
Pike Place Farmers Market 5273 x 2309 (12 megapixels)
Space Needle and Mt Rainier 6388 x 2366 (15 megapixels)
Seattle waterfront from the Space Needle 8861 x 2062 (18 megapixels)
Pike Place close-up 11323 x 3026 (34 megapixels)
As LiveLabs mentions on their website - an easy way to add hi-res images to your eBay listing, real-estate website, ecommerce store, blog, etc...