Okay, here you go:
Catan (link)
Abalone (link)
The Catan site offers two computer versions, one for the basic rule set thnat can be played for free online against the computer, and a quite competently done, nice-looking conversion of all expansion rule sets as well. I even bought that game for curiosity, and I like it.
The Abalone program offered, is free. But be warned, it is one of the two top softwares in the world for this game, and it indeed plays absolutely lethal if you let it off the chain. That you indeed start on level one and stay there for a long time, is vitral to prevent you from committing suicide in frustration sooner or later. I mean, the program is a killer. There is no real gap between the human world elite players, and the software. So, you are warned.