ow this is a beta app that just rolled out, i don't think you can get it from the official website or the app repositories, this is a great app that lets you watch TV from a huge selection of nice channels via online streaming, its great, all what you have to do is launch the app, choose the channel in a very nice bar of channels, and your good to go .
more info and where to download this great app http://discussions.mea.nokia.com/t5/Maemo-Devices/SPB-TV-free-tv-on-your-n900/td-p/730629