I made this in about an hour, after I couldn't find one I needed. Looks good with the desktop also. Font is copperplate, all the other geeklets are available on the site.
The geeklet will show the percentage of your battery remaining, and will change colour to red when it drops below 20% which can be changed in the 8th line. The colour can be changed in lines 17 and 18. The colour of the text when above 20% can be changed in the 27th and 28th lines.
*Edit: The link doesn't seem to work so here is another link to google docs: Battery Glet
