You can't join a house, ever. The closest you'll ever come to joining a faction, is when your rep with them is so astoundingly high that it says your part of that faction when other players see you, simply because they like you so much you might as well be a part of the faction.

People have it all wrong these days, instead of discriminating and hating others for being black or ugly, we should practise fairness and hate every living thing equally.

@Tartan: While you can't join a specific house if you're playing MP Freelancer online you may be able to join a faction that holds the same values as some of the houses in FL. Your best bet is to find a good RPG mod in the Download section and download that mod then go to the forum for that mod. I strongly suggest Asgard v1.1 But there are others. You just need to look around some.