Normally you would download YouTube on your Nokia N900 but this time Maemo comes with @scene which is something similar to YouTube but a bit better in a few ways.

It is powered by YouTube but @scene can work with other web based video services. The latest version that I found is V1.0.6.

It is available as a  beta version and @scene is one of the few applications written in Qt designed for Maemo. Its high optimization of the application of superior consumption and the video contribution of YouTube makes it easy for the user to access it through @scene rather than waiting in the web with a slow web browser.

Nokia N800, N810 and N900 devices running on Maemo with Qt 4.5 as well as Ubuntu 9.10 or newer on desktop Linux support @scene.

@scene does have an advantage of that it can’t be used in portrait mode but it makes no difference as you are going to watch the video in landscape mode.

The menus present in the @scene home screen are Web feeds (RSS) including Top rated, Most viewed, Most discussed and Most recent. Community features including Comment, Share, Rate, Upload, Messages, History, Statistics, Search and Play, Automatic full-screen playback, Save to Favorites,Playlists, YouTube service plugin, Offline playback

So hook up your earphones to your N900 (use @scene) and start listening/watching to videos.