when a player has less than 6 months left of his contract it should be possible to sign him at the end of his contract, but on most players this i not possible, i can only make an offer.
English rules state that you can only enter talks with a player, without his club's permission, after the 3rd Saturday of the May of the final of year of his contract. Or about a month before his contract runs out.
Fifa rules are that this can take place 6 months before the player's contract runs out but you do have to notify the other club before you start negotiating.
Looks like FM09 is using English rules for England and English clubs. No idea of elsewhere in Europe yet though.