User FAQ
If your question is not posted here, try the search tool in this wiki, http://maemo.org and http://www.internettablettalk.com/forums/ (or even your preferred Internet search engine).
How to get more memory to install applications
http://wiki.maemo.org/Booting_from_a_flash_card
How to encode video files for playback on the N800/N810
http://wiki.maemo.org/Video_encoding (also includes information on video streaming)