Favicons
From WikiLinks
Favicons are little 16 x 16 pixel icons that are served by the browser in the URL bar (and on the window's tab if you use a browser that supports tabbed browsing). I used to not bother with them, but I've just noticed that if you don't have one (even a dummy file), it creates an error in Apache's error log. As it's quite easy to do (just put a favicon.ico file in the root of your website), I thought I'd better fix it.
There is also an easy way: just save the file out as a png, rename it favicon.ico (or anything.ico for that matter - as long as it's .ico it seems to work), and upload to the root of your site.
If you're keen on having your visitors see the favicon, you might also want to put this in the source of your page: <link rel="shortcut icon" href="/favicon.ico" type="image/x-icon">
Favicons don't have to be .ico or .png files, they can also be GIF and even animated GIF, an example can be seen here (may not work in all browsers, it worked for me in FireFox on MacOS X)
