Digital Spy have released some rumours about the Fires of Pompeii but these should only be taken as rumours...here the article is:
"We're positively erupting with teasery hints about what lies in store for The Doctor and Donna when they turn up in Pompeii 79AD. Here are several clues about the content of their adventure, some cryptic, others fairly blunt. As an added bonus, we've chucked in three red herrings into the lava this week for you to fish out.
The Tardis is sold, but without The Doctor's consent.
The Doctor reveals himself as a Fawlty Towers fan with a quip he makes about Donna.
The time travelling pair are already known to some inhabitants of Pompeii.
An escape pod is used at some stage.
Donna uses her mobile to send Wilf a picture message of the erupting volcano.
Rose Tyler is glimpsed hiding behind a rock in the centre of the volcano, watching The Doctor.
The Tardis translation device isn't limited to voices.
Donna is turned to stone.
The Doctor speaks about his father.
Pompeii residents believe that Donna is Welsh.
The Shadow Proclamation (which would be a great name for a band) crops up again.
The Doctor talks about Status Quo and quotes Bill And Ted's Excellent Adventure."