I believe that Ellison won his out-of-court settlement (not lawsuit) and got his acknowledgement in the film's credits due to some comments Cameron made in a Cinefantastique interview.

Cameron, perhaps unwisely, named Ellison's two Outer Limits episodes as influences on his script (a third one, "The Man who was Never Born," starring Martin Landau and not written by Ellison, may have also been named). Before publication, Cameron asked the interviewer to strike those comments. The interviewer did, but he sent a copy of the unedited transcript to Ellison.

(This is Ian, FINALLY getting the goddamn OpenID thing to work)