Is there a plugin that does this?

I want to make my server unique by making all the / commands to ! commands, so instead of /help its !help. I think this would be REALLY cool for my server and I was wondering if there is a plugin that does this and if there isnt how simple this would be to do. It would make all the commands on the server !, not just the commands in the plugin,

 

No! Absolutely not! You (if you want to) can change the command character in your client to ! not /, but that is TOTALLY (ish) undoable with a plugin.

 

other servers have it

 

This is kind of a large bump I can say my self, sorry for this, but you can make this with a plugin, it is totally doable, just to clear things up.

 

You could try MyCommand. It allows you to create new commands or aliases for the existing ones.
The only problem is, you have to configure EACH command individually, and that would take A LOT of time.
On the other hand, I don't know any other plugin capable of doing it. Sorry.

 

Maybe with that. Otherwise....no.

 

This isn't possible with the new API for Bukkit. You would have to make your own API to make this function correctly.