When I mentioned the religious war that might break out about MDA vs DSL this actually gives the essence of these kinds of differences. The difference is not in those terms or the technical content they stand for but in the people that get behind them.
It is possible to create a DSL with MDA. There are a number of languages based on MOF the OMG keeps reminding us, like UML but also Corba and the CWM. These can be referred to as DSL's. If those examples seem to generic in nature to consider them as DSL I'm sure a short introduction into MDA wil convince anyone that contructing a DSL using MDA is possible. And of course it is possible and probably the most sensible choise to base DSL solutions on a metamodel that combines and relates the different DSL's. So the only difference between your avarage MDA or DSL solutions is whether the metamodel is MOF (open) or that of a vendor and thus perhaps proprietary. We'll probably see a lot of time being spend on these subjects without it resulting in anything that touches upon this subject.
Maybe its best to stick to the as for now still academic group of the generative programming people with Krzysztof Czarnecki as one of its exponents. They include almost every modern subject in IT on their stride towards generating software. And as long as they write great books about it that's just fine with me.