afaik channel ten doesn't release BB on DVD, there's way too much material (30 minutes or more broadcast each day for 3-4 months) for a complete DVD set and the show's not popular enough for a highlights DVD to sell.

The BB Uncut show that showed housemates nude was cancelled later that season because of lots of complaints and controversy, but rumour has it that it'll be brought back for the 08 season which will start at the end of april.