I've seen this report, and the validity of it is questionable at best. The GCN version of SC2 outsold both the XBox and PS2 versions by a substantial margin. Doing this will only cut Namco's potential sales in half. It would be a terrible business move.
Yeah, a few mags are reporting it, but those same mags also reported that Viewtiful Joe 2 and Resident Evil 4 were going to remain GCN exclusives. This decision makes zero logical sense.