How to add a contract
In order to watch and interact with a contract already deployed on the blockchain you need to know its address and description of its interface in JSON format.
In the MIST Wallet GUI, click on the "Contracts" tab, then "Watch contract". You can name the Contract as you like. Fill in address and the ABI interface in JSON format. For the DAO, you will get these data on daohub.org.
Click OK, and you're done.
After you have added a contract, the contract appears on the Contract tab in the MIST Wallet GUI. You can read the contracts data (left side of the screen) or call the contracts functions (right side of the screen).