I have a question for you: I would like to have a kind of game where me and my friends can play one turn at a time, recieving a notice by email for example, and so the game could last for weeks or months, but we would not have to be playing the game live all together.
I'm not opposed to the "PBEM" multiplayer model in general. I think that it would work really well for digital versions of some games. That said, I'm not sure it would be the best for Talisman. An individual turn in Talisman is pretty short: roll dice, move one way or the other, encounter whatever you find. Using the PBEM model with more than two players would result in five seconds of play followed by several days (or weeks!) of waiting on other players to take their turns.
Granted there's not a lot of long-term strategy that needs to be remembered in Talisman, but I'm not sure I'd enjoy playing a game with such short intervals of activity via PBEM.
I think the PBEM model works much better for games where each player has a significant number of decisions to make in one turn and/or games that are known for having long periods of downtime between turns when played "face to face." For a game like Talisman, the two forms of multiplayer that I think would work best are "live online" (potentially with the option to pause a game and resume later) and hotseat multiplayer on a single device.