Here's a recording of the leap second announcement on WWV (03 December 2005 @ 2304 UTC, 15mhz, Sony ICF SW7600GR):
2005 leap second announcement from wwv.mp3 (0:58, 463kb)
"Your attention please. At the recommendation of the international time bureau, a leap second will be inserted into the time broadcast of radio stations WWV, WWVB, and WWVH. Commencing at 23 hours, 59 minutes, 60 seconds UTC on December 31st, an extra second will be inserted into the NIST time scale. This adjustment is required to maintain internationally coordinated universal time in close agreement with UT1, or astronomical time."
Edit: Thanks to shortwavemusic for resolving the "NIST time scale" part of the transcript.