It is my belief that the main reason that google maps has not been developed for Maemo 5 is because of the relatively small user base that the platform currently has. It could also be because Google sees open source OS's as more of a threat and does not want to support them with apps even though it doesn't follow they're usual business strategy of trying to reach as many people as possible. Or of course it could be something else I haven't thought of, but for the purpose of this question let's assume it's the first thing.

I've read a lot of people saying that with the implementation of Qt 4.6 we should a lot more developers making apps for Maemo 5 as it will be a lot easier to port the apps for multiple OSs. I'm not a developer and my knowledge of things like this is very limited at best but is google maps the kind of app that could be written using Qt and do people think that having Qt4.6 will make it more likely that we see google maps (or other Google apps) coming out for Maemo 5? Or have I completely missed the point of Qt?

The problem with taking Google maps as an example is that it's proprietary to Google. There is no public library (that I'm aware of anyway) which a developer can use to interface with the google maps/earth repository. So unless Google would release a public library which allows access to their maps or develops their own app for Maemo or Qt, we won't see a native google maps app I'm afraid.

Qt is fundamentally a user interface development library which allows developers to easily code the user interface layer of the application. (It also includes libraries to interface with databases, files, network etc, but those are secondary to the user interface components) Without Qt (or another cross platform library), to develop an app on multiple platforms you'd typically have to develop the user interface separately for each platform. Each platform will have a different set of calls to put up a button for example. With Qt, the calls to create that button are the same for each platform so you only have to develop the interface layer once and it is portable across the other platforms supported by Qt.

qtwebkit?
.......

Google will never release public library because they have bought satellite images for showing only in their programs.

I think the app you are searching for is Maemo Mapper