I've just received this via email - it's from a very unusual source (he won't mind me saying that!) but I think the majority of what's being reported is true. If so, it's going to make for an interesting second season...!
"Hello Jack, this is from my reliable friend...
There's a plotline involving a soldier from 1st world war (called Tommy) who is apparently frozen at the Torchwood HQ - he is then defrosted and has to do some time travelling and self sacrifice back in the past in order to save the world ... oh and he and Toshiko (forgive me if I have got her name wrong!) fall in love. Oh dear oh dear!
Jack's father and brother make a few appearances... apparently [spoiler cut for the protection of future plot twists!]... hmmm room for further development there methinks .
Oh and Owen is supposedly turned into a monster for 2 episodes!!!!"
If you have any (genuine) information regarding Torchwood 2 then get in touch with me via the regular address.