The catalyst that pushed it over the milestone was Friday's release of the iPad 3G, which in and of itself sold 300,000 units. According to Apple, that push brought total iPad sales to the 7-digit mark.
"One million iPads in 28 days—that's less than half of the 74 days it took to achieve this milestone with iPhone. Demand continues to exceed supply and we're working hard to get this magical product into the hands of even more customers," said Steve Jobs in a statement.
Despite the fact that Apple is usually dodgy when it comes to numbers, today's press release was filled with them. Sales on the iBookstore have now gone over 1.5 million titles, and more than 200,000 apps are now available on the App Store. Around 5,000 of those were designed specifically for the iPad, while others are merely ported over the iPhone App Store, or jointly developed and marketed for both platforms.
Apple shares went up a higher-than-usual 2.0%+ in early Monday trading.