
I've just spent five minutes covering my Google toolbar with these custom buttons. Here are the Google instructions:
- Install the Google Toolbar
- Go to http://slashdot.org/
- Right click on the search box at the bottom of the page and select "Generate Custom Search..." from the menu that appears

- Click on "Add" and then "OK" in the Custom Button installation dialogs
- Congratulations! You've created a custom button for Slashdot on your Toolbar.

Not every website has an option for a pretty icon to appear. In that case I get a magnifying glass icon appearing on the Google toolbar, and the only way to find out where it leads is to hover over it. It gets tedious when you have a whole line of identical unlabelled icons. Some websites have no search box.
The easiest thing with both of those is to bookmark the site and add the bookmark title to your Google toolbar. Click on Bookmarks, then Bookmark This Page, then save it in the Bookmarks Toolbar folder. Hey presto! It appears on your Google toolbar.