The first same-day release of the written transcript of a Supreme Court argument is now available, at this link. It is in the consolidated cases 05-547, Lopez v. Gonzalez, and 05-7664, Toledo-Flores v. U.S. The transcript was posted at 2:15 p.m., three hours and 15 minutes after the conclusion of the hearing.
UPDATE: The second transcript, in 05-493, Ayers v. Belmontes, was posted at about 3:30 p.m., about three and a half hours after the hearing had ended. It can be found here.