The Daily Telegraph has now provided fuller details of the audios that they are giving away free from next weekend. Details here.
Saturday 24th: The Runaway Train, read by the new Doctor, Matt Smith (and written by Oli Smith)
Sunday 25th: Part One of Pest Control, read by David Tennant
Monday 26th: Get a voucher that you can redeem in WHSmith for Part Two of Pest Control.
Tuesday 26th: Voucher for Slipback, starring Colin Baker and Nicola Bryant
Wednesday 27th: Voucher for Exploration Earth starring Tom Baker and Sarah Jane Smith
Thursday 28th: Voucher for Genesis of the Daleks, abridged novelisation narrated by Tom Baker
Friday 29th: Voucher for Mission to the Unknown, original soundtrack with narration by Peter Purves