Amazon's own movie download store and iTunes competitor has just launched. Amazon offers full length movies as well as TV shows, with shows like Prison Break and 24. You can either buy the shows outright or just rent them in WMV format for watching on your computer or a portable media player.

You have to use the Amazon Unbox software to watch movies, and you can't burn it to DVD so you can watch it on your TV. So far a full season of 24 costs $38.21, compared to $1.99 for an individual episode and the iTunes price of $42.99. We gotta hand it to Amazon to launch the movie download store just a few days before Apple's "Showtime" event. - Jason Chen