Apple today announced that it has sold over 1.7 million of its iPhone 4 through Saturday, June 26, just three days after its launch on June 24. The new iPhone 4 features FaceTime, which makes video calling as easy as one tap, and Apple’s new Retina display, the highest resolution display ever built into a phone, resulting in stunning text, images and video.

“This is the most successful product launch in Apple’s history,” said Steve Jobs, Apple’s CEO. “Even so, we apologize to those customers who were turned away because we did not have enough supply.”

iPhone 4 also features a 5 megapixel camera with LED flash, HD 720p video recording, Apple’s A4 processor, a 3-axis gyro and up to 40 percent longer talk time—in a beautiful all-new design of glass and stainless steel that is the thinnest smartphone in the world.

Apple may have sold 1.5 million iPhone 4s in the first day. The 1.5 million figure comes from Yair Reiner of Oppenheimer, who notes that this kind of guessing has “become something of a national sport.” His figures do seem solid and the math really isn’t that complex. We know that Apple revealed some 600,000 iPhones had been pre-ordered in the U.S., a figure boosted by 100,000 non-reserved units in Apple stores across the U.S. during yesterday’s first sales. If 50,000 went through the cash registers at Best Buy too, that brings the U.S. sales total to 750,000. Based on the fact that over 50% of iPhones are found overseas nowadays, Reiner then (conservatively) multiplied this figure by two. This gives a guesstimated sales total of 1.5 million units.

Apple sold its 3 millionth iPad, just 80 days after it first went on sale in the U.S. Now, despite the fact that one analyst has claimed that its popularity has peeked, that’s a whole lot of $500+ devices sold in under three months. Back in February, Apple estimated 10 million units leaving its headquarters before the end of 2010 an with another nine countries getting access to the iPad next month, that’s a safe bet.

Last week’s mess, with both Apple and AT&T’s Web sites crashing under the demand for the iPhone4, Katy Huberty, an analyst with Morgan Stanley, reckons that, by the end of 2011, there should be 100 million iPhone subscribers worldwide which is an increase of 70 million from the end of 2009. Crazy!

The new version of the iPhone has black glass and a stainless steel rim, plus front-facing camera for video conferencing. The new battery is capable of 7 talk hours over 3G, 6 browsing hours over 3G, 10 browsing hours over Wi-Fi, 10 hours with video, 40 hours with music, and 300 hours on standby”. Apparently, it has ‘four times as many pixels’ per inch resolution in the screen, compared to the previous iPhone (326 pixels) This iPhone 4 also has a new accelerometer to make 6-axis sensing, and an extra microphone for canceling out noise. The official release date is June 24. Prices should be $199 for 16GB and $299 for 32GB.