Once you have a few Apps in the marketplace why not market them ‘in app’:
This can be a relatively pain free process, simply requiring either a block of templated code, or perhaps a specially built DLL containing references to your apps. I opted for the former (I am a little lazy) and have some templated XAML:
which pulls it’s content in from an RSS feed on my own site here:
One of the advantages of adopting this approach is that, as I add new apps to the Marketplace, all my existing apps are updated with a reference to that new App.
Consuming any XML based feed in WP7 is as simple as reading Scott Guthrie’s blog:
NB There are other ways you can advertise ‘in app’ which I will explore in a future blog post.