Webmail is gone in Mountain Lion. Not all users are pleased so it is time to install RoundCube mail to give them their beloved webmail back. RoundCube was used with Lion as the webmail solution and can be download from here.
But just installing it is not enough, it has to be installed as a full featured webapp in order to integrate nice with Mountain Lion. The standard security settings of the onboard PostgresQL database are pretty tight. They can be loosened, but to avoid potential update problems we’ll install MySQL as a second database server. Note that installing RoundCube mail requires some experience of working at the commandline.