I like using Scrapblog for creating scrapbooks. It is a free online program that is very versatile, I use it often, read more about ways I used Scrapblog for my genealogy.
Another application I'm trying out is Smilebox, it isn't quite as flexible as Scrapblog, but you can make it your own and publish to your blog. Here is an example:
|Make a Smilebox postcard|