Just been looking at the PS3 UK website and they have set out some details regarding Online play.
Here
I would rather Polyphony take their time in releasing it as it will be a great game. I am also glad that Rockstar did the same for GTA IV. I am hoping though that people who have Prologue will be able to get the final release discounted and/or be able to keep all saved data from Prologue into the main game.