The breathless and somewhat misleading headlines in the Australian media notwithstanding (here and especially here), there's a great video that just came out of HMAS Waller (SSG 75) sinking an unidentifed U.S. hulk with a Mk 48 Mod 7 CBASS torpedo. Check it out:
This SINKEX occurred off the coast of Hawaii in conjunction with the upcoming RIMPAC 08 exercises. It brings a tear to an old submariner's eye to see a skimmer's bow slipping silently beneath the waves...
Bell-ringer 1539 24 July: A commenter thinks the SINKEX victim was the ex-USS David R. Ray (DDG 971); this post last month from Steeljaw Scribe would seem to confirm that this is likely.