icos are icon files. just do a search for icon packages or soemthing. deviantart.com has some packs, you can also make your own. make a file in photoshop or whatever and use irfanview to convert it to an ICO file. you can also check your dll files that icons are stored in and extract the icons. i got some icons for my apache server.
if your looking for an all inclusive pack that works easily .... then im not sure
I know what they are I just am having trouble finding more I like. I used ressomething to open the dll files. I spent about 4 hours on google and emule but only got a few. A lot of awesome ones are in .sht format and the prgrm to open them pissed me off and wouldnt uninstall so i had to system restore.