I\'m about to publish a new version of an app to the Market. In order to avoid any potential problems once its been pushed to the Market and people get notified of an update, I\
The closest I think you can get is to put the APK somewhere, and download it on a phone. That is about the closest you can get to the real market situations, with the only difference being that you need to add the "unknown sources" option.
(on a sidenote: you can get an error installing an apk with the same package-name, but a different signing.)