In essence, it's not a regular thing, but a travel agent (Croydon Travel in Sydney) charter a 744 and fly it over the Antarctic every 6 months or so. Not exactly cheap, around $1500 if memory serves. Leave Sydney, and fly to Antarctica and back, all up, I think about a 12 hour journey or so.
You circle around some of the Antarctic stations, and they put the Captain speaking to the stations over the PA so everyone can hear. Very spectacular.