http://developer.android.com/resources/samples/Home/src/com/example/android/home/Home.html

 /**
     * Loads the list of installed applications in mApplications.
     */
    private void loadApplications(boolean isLaunching) {
        if (isLaunching && mApplications != null) {
            return;
        }

        PackageManager manager = getPackageManager();

        Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
        mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);

        final List<ResolveInfo> apps = manager.queryIntentActivities(mainIntent, 0);
        Collections.sort(apps, new ResolveInfo.DisplayNameComparator(manager));

        if (apps != null) {
            final int count = apps.size();

            if (mApplications == null) {
                mApplications = new ArrayList<ApplicationInfo>(count);
            }
            mApplications.clear();

            for (int i = 0; i < count; i++) {
                ApplicationInfo application = new ApplicationInfo();
                ResolveInfo info = apps.get(i);

                application.title = info.loadLabel(manager);
                application.setActivity(new ComponentName(
                        info.activityInfo.applicationInfo.packageName,
                        info.activityInfo.name),
                        Intent.FLAG_ACTIVITY_NEW_TASK
                        | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);
                application.icon = info.activityInfo.loadIcon(manager);

                mApplications.add(application);
            }
        }
    }