First signs of GTAIV downloadable content

Microsoft have made an announcement regarding GTAIV's downloadable content appearing in Autumn this year. You can read their statement below;

In autumn there will be news from Liberty City; the first episodes of GTA IV will be available for download exclusively on Xbox Live, underlining Xbox 360's leadership role in the field of digital entertainment.

I believe that PS3 will also be getting downloadable content but this does state that it is an Xbox 360 exclusive. Perhaps PS3 will merely receive the content at a later date. It is also interesting to consider how the PC version of the game will come into the equasion being part of "Games for Windows" and all.