No idea if there's any bearing, but here are the iPod MSRPs:

1st gen, Nov 2001
5GB - $399

2nd gen, Jul 2002
10GB - $399
20GB - $499

3rd gen, Apr 2003
10GB - $299
20GB - $399
30GB - $499

iPod photo, Oct 2004
40GB - $499
60GB - $599

4th gen, Nov 2004
20GB - $299
40GB - $399

iPod photo, Jan 2005
30GB - $349
60GB - $449

5th gen, June 2005
30GB - $299
60GB - $399

iPod 2.5, Nov 2006
30GB - $249
80GB - $349

Granted, the iPod doesn't have the cell service income, but it has brought in a ton of iTunes income. Plus, it's missing a lot of the hardware components that the iPhone has (wifi, bluetooth, touchscreen, etc. etc.)

The ATT factor is an unknown here, but again, I don't see anything incenting Apple to reduce prices of the current phone. Future phones could be cheaper or pricier depending on any number of factors. But a $50, or even free?, iPhone at some point - I don't see it happening. Just MHO.