Apple has announced that the 3G iPad will indeed ship to US customers in late April. 30 April to be precise.
Customers who pre-ordered before the shipping date slipped to 7 May will have their iPads delivered on the last day of April, with US Apple Stores having stock from 5pm on that day.
Given that the shipping date had just slipped, its unclear how many units Apple will have in its retail stores. Demand is likely to be high, and stock might be low as a result.
If you managed to secure a 3G iPad for private import into Australia before the change in shipping date, you should be seeing it arrive early in May.
The local iPad release is still scheduled for late May for both Wi-Fi and 3G models, with pre-orders available from 10 May.