The Auto App Mart makes it easy to provide access to your applications and still see all the download information for your apps.
You can contribute by signing up and uploading your auto apps. You can mark them as free, for a price, or donation. From your AAM back end, you can see all of the relevant stats. And you can provide feedback or ask questions if there is something that you cannot find, or functionality that you think that the AAM should provide.
If you are not a current member of the mp3Car community or have never before developed auto apps, you can get some development ideas by looking at the mp3Car Software Development forum and checking out all of the front ends as well.