Preview at WWDC likely in June, followed by September launch.
John Gruber: No Camera on Apple Tablet
And, for what it's worth, I'm hearing there is no camera, webcam or otherwise, on The Tablet.The much-followed Gruber has several times in the past offered accurate information on forthcoming Apple products, most recently correctly revealing Apple's October product unveilings (with the exception of his "wildcard" multi-touch trackpad gadget claim) the evening before their release.
Little more than speculation has suggested that Apple's tablet will include a digital camera, with such rumors sparked in early April with a report that Apple had ordered both 3.2- and 5-megapixel camera sensors, with the former slated for what became the iPhone 3GS and the latter for a product scheduled for introduction later in 2009.
Sources were also fairly quiet about whether the tablet would offer a webcam until relatively recently, when claims began to increase. The earliest widespread claim of a webcam appears to have been in mid-August with reports that Apple would offer two models, with and without webcam. Webcam speculation increased significantly yesterday after France Telecom executive Stphane Richard appeared to offer some confirmation of a forthcoming tablet release including a webcam option for videoconferencing, although company representatives quickly clarified that Richard's comments had been misconstrued.