Getting media content onto your tablet
UPnP Media Server
Universal Plug and Play is a set of protocol for device inter-communication, sharing data in your home network - for details see wikipedia article on UPnP.
UPnP Media Servers can be used to share your media content (music/video/pictures) with your tablet. All you need on your tablet is an UPnP capable application like Media Streamer or Canola for example.
To set up your own UPnP Media Server I recommend to take a closer look at FUPPES - short Free UPnP Entertainment Service, because it's free and platform indepentent. It's available for Unix (Linux/BSD/MacOS X) and Windows.
...to be continued soon