The online Apple store has currently no iPhones in stock. Both the 8GB and 16GB iPhone are marked as "Currently Unavailable".

This could also just be a store glitch, but we also already learned that week that O2 has run out of iPhones in the UK.
It is suspected that this shortage already heralds the 3G iPhone, but I still think that Apple will continue to offer the normal iPhone for a while. Not everybody gets 3G coverage.
Additionally the anticipated launch of the 3G iPhone is June. If Apple already runs out of the current iPhone model in early May, they would be not selling iPhones for several weeks and loose money.
More details on Apple Store. Via Apple Insider.