This web page is a preliminary doodle for a Javascript augmentation to a web anchor that pops up a tooltip containing a search box that allows the user to search for terms with the site specified by the link using Google and the site: switch.
In this preliminary test, the search URL is hardwired to micro-info.blogspot.com. The pop-up is not tuned for form entry, so you may need several goes at hovering over the link before you can get a text cursor in the text box, your search term entered, and the Submit button clicked. But if you can cope with all that, it does work (in Firefox 1.07, at least...)
Step 2 is to automatically pull out the URL from the href attribute, step 3 is to fix the usability of entering the search term in the pop-up tooltip.
The popup menu is courtesy of the wz_tooltip.js library.