Most of the Android applications can be found at Android Market. However, some of them are not in there. They are offered at other website for download. Android application is coming with .apk file type while Microsoft Windows Mobile with .cab file type. In order to non-Market .apk application on Android, you need to enable ‘Unknown sources ~ Allow installation of non-Market applications’ in Applications at Setting. Just tick on it and you can install non-Market application right now. Else, you will get ‘Install blocked’ message pop up.