Play are doing it at £10.99 and it will feature two episodes:
1. The Christmas Invasion (2005 Festive Special episode)
2. New Earth
The other announced volumes are due:
Vol 2: 05/06/2006
Vol 3: 12/07/2006
Personally, I think I'll hold out until the complete Season 2 Box Set is released. That is due on 20th November 2006 here in the UK.