They are most definitely sold separately (
http://iphone.tomtom.com/en-us/faq.html), making the "bundle" price here in North America $220. I'm still not convinced that this is going to fly given that this price is near the upper end of standalone GPS devices now. However, the dock does charge the phone, it has a built-in speakerphone, and it has 3.5mm audio out, so I suppose it isn't a bad deal for those without other solutions for these desirable features. It does also make it possible to pocket your GPS quite easily for walking directions. Time will tell. However, I'm guessing that both the app and dock prices will fall 25+% quite quickly as demand reveals itself to be lackluster.
Ironic that Garmin + AT&T also "released" their NuviPhone today. That combo is even less desirable to me, except for the fact that you get Garmin's awesome software...