It's not abandonware etc but Gamespot has an open beta of settlers 6 at present which if you can stand the 10+ hour download of 1GB works pretty well and is quite a nice game if a little drawn out.
You only get the tutorial level for single player but you can play the multiplayer LAN and online games fully.
I will have to d/l settlers 1 this weekend for a comparrison
.
Settlers 6 open Beta -
http://uk.gamespot.com/pc/strategy/thesett...=result;title;0