Rotation Lock Does What It Says, Even For Landscape
While most Android devices have a setting that prevents automatic screen rotation, it usually locks the orientation in portrait mode. There’s no way to lock it in landscape – at least not without an app.
That’s why forum member madmack developed Rotation Locker, with which you can choose whether you want the screen locked into portait, landscape, or not at all. Compared to other apps in the Market, it’s free and doesn’t have continuously running background services eating into your battery life.
Download the app in the forum thread.