Lets you choose different protocol icons for different accounts so that you can tell the difference between, say, a personal XMPP account and one that you use for business.
How to use
After installing and enabling the plugin, go into your account preferences into the advanced tab. Down the bottom should be a new option 'Protocol Icon'. Fill that in with the name of an image file in your pixmaps/pidgin/protocols/16 directory, excluding the '.png'. eg if you want to set the Yahoo icon, type in 'yahoo'