Don't buy "composite to VGA" cables, it won't work. Composite and standard monitor VGA cable connection are two totally different standards, and You need converter (containing electronic circuit, not just cable crossing) to connect composite into analog monitor input. Something like that:

http://www.aliexpress.com/product-fm...olesalers.html

(AFAIK this is cheapest model available).

Also, trans-coding N900 composite video output to HDMI or whatsnot is pointless. The best You can achieve (using PAL) is still worse in terms of resolution, than N900 native screen. Unfortunately, blame Nokians for lack of HDMI out.

Still, video out is *very* useful, when connecting N900 to LCD TV's + using mouse and keyboard (HEN, or bluetooth). With addition of VNC or rDesktop (the latter for winboxes) You essentially have full-fledged desktop PC power in Your pocket. But, even without fast internet connection, Easy Debian is also powerful desktop PC experience, in tandem with big "monitor", mouse and keyboard.

BTW, if You're connecting VNC via (w)lan, You can tweak x11vnc (on N900) settings, to make it much more responsive.
Just read documentation for that - with correct setting, it's almost real-time (for sake of testing, I used Tux Racer on N900 via VNC - it was playable, "almost").

/Estel