Iphone 3gs compatiblity with Tom tom sat nav

Question

just got anew I phone 3GS - after checking it had bluetooth etc ; I assumed it would interface using bluetooth, with my Tom Tom not only for hands free calling but also to download up to date traffic information - as did my old Samsung SGH G600. The telephone calling is fine but apparently Tom Tom now tell me the sat nav units are not compatible with iphone for getting the traffic information downloaded via the internet.
I never dreamt (perhaps naively) that a major phone supplier like Apple would not automatically be compatible with Tom Tom.
Anyone come accross this problem and got a solution - other than buying a new sat nav or an additional sim card for my old phone plus a subscription or pay as you go cost of course!!

Answer 1

Thanks for info. I know there is/are an app(s) for this but not fully investigated it yet as I want to be certain I cannot just 'fix' my current problem and continue to use Tom tom with iphone as i did previously with Tom Tom/Samsung.
If I do look have to look for alternatives Tom Tom do a new satnav with 'hd traffic live updates ' which I understand does not need a phone connection at all - sounds interesting