DeWitt Clinton has
a nice tutorial on adding an OpenSearch plug-in to your website.
OpenSearch is a search engine description standard supported by both Firefox 2 and Internet Explorer 7 that makes it easy to customize the search engine. For example, if you’re using Firefox 2, you can left click on the down arrow next to the search box and see an option to “Add Brian.Carnell.Com”, which will give you the option of search this site from the search bar.
I’m not necessarily sure why you’d want to do so, but it’s there if you’re as obssessed with my life as I am.
The OpenSearch setup for this site uses the internal search engine, but Clinton’s tutorial shows how to set one up a Google search of just your site. But the example is easily modifiable to use your own blog or web site search engine.