According to Wikipedia, a Torchwood audio play titled "Lost Souls" is due to be broadcast on BBC Radio 4 on September the 10th. The play was written by Joseph Lidster (who also wrote the TW episode "A Day in the Death").

"Lost Souls" will feature the voice talents of John Barrowman (Captain Jack), Eve Myles (Gwen), Gareth David-Lloyd (Ianto) and Freema Agyeman (Martha).

On Amazon.co.uk the release date for the play on CD is September 18th.