Apple's shipping estimates for the iPad quickly ballooned to 4-5 weeks at the device's launch, and have been gradually improving since that time. With turnaround times now at or under a week, Apple appears to have finally tooled up sufficiently to nearly meet demand.
Apple's iPad 2 debuted late in the first calendar quarter of 2011, and the company fell far short of most analysts' iPad sales estimates for that period, with the company noting that a drawdown in supplies of the original iPad and ramping of iPad 2 production meant that the company essentially sold every iPad it made during the quarter. Apple's supplies undoubtedly improved during the second quarter, and the company will reveal its shipment numbers for that period later this month.
Update: Apple's European online stores have now been updated with the new 3-5 business day shipping estimates.