TomTom for iPhone has appeared in the New Zealand iTunes app store. Probably because NZ is in the future and it's Monday there already. In theory (theeeeeooooory) the TomTom app is having a Monday release and will appear in local app stores as Monday appears for the region.
That said, the app looks good. It's about $83 USD, so about the same as the Navigon, and a 1.2G download, so about the same there too. A quick look at the features shows it's pretty much the same as well, with a slightly different look and so on.
The big issue here is that a) this price is only for the app, not the magic holder system that was demoed and b) you can (apparently) get a TomTom standalone unit for that price. So unless the TomTom holding arm is cheap, I think they might have priced themselves out of the market a bit. Course, to do the same with the Navigon (or any other GPS unit for that matter) you still need to pay $40-150 on a holding system.
Guess we'll see what happens on Monday!