First of all, it's called Black Mesa and not Black Mesa: Source. Black Mesa will be released earlier, it's basically done it just has to be released. One of the mappers said 'soon' earlier in May, but who knows what that soon means. If the developers are awesome it will be released this summer. Nothing is known about Episode Three, Marc Laidlaw keeps it very secretive... let's expect 2012 if Valve is awesome.