There is always the Essentials Plugin. Essentials comes with Essentials signs, so you can customize your signs any way you like. You can create command signs, colored signs, etc. Best part is that it is almost always updated. But if Essentials isn't your pick, you can always use other plugins made specifically for Command Sings, because Lax is right. You can't judge a plugin by its last upload date.
I would suggest CommandSigns. Download Vault and CommandSigns and you should be good to go. CommandSigns is very helpfull and has multiple features. Btw, Any plugin works with bukkit as long as it is written correctly, so you don't have to look at when the last update was.
