I'll shortly bundle MMCPool's minerd with the wallet and introduce a menu option allowing wallet users to pool mine with just a single click. It'll launch an external process running minerd properly parameterized for MMCPool.
Any other pools using the same network interface (capable of using the same client software with different parameters) that would like to be included in the GUI - please let me know asap.
We'll need to have a careful think about how to standardize an interface for the GUI to talk to pools, but for now I just want to get it up and running quickly.