<b>But isn't abandonware legal?</b>
Simple answer, NO. Despite the fact that publishers no longer derive revenues from these games since they have stopped selling them (and any revenues from retailers that still sell them were gained a long time ago, at the time of sales), it is illegal to distribute them so long as copyright holders have not released them into the public domain, and 95 years after the games' release have not elapsed.
<font size=1>Taken and modified (slightly) from the underdogs FAQ</font>