Pre-orders for Apple's iPhone 4 kicked off this morning and the demand for the product has taken its toll on Apple and AT&T. Reports are flying in saying that trying to pre-order the iPhone from Apple's site is hit or miss, with some users repeatedly starting the pre-order process and then being kicked out. Apparently AT&T isn't faring much better, as Boy Genius Report has been told that AT&T's in-store systems are bogging down under the weight of the demand. Finally, it seems that there are even lines forming outside of brick-and-mortar stores, as you can see in the photo above. It definitely seems like Apple will have another hit on their hands, although we're sure that there are some disappointed customers that can't order the white iPhone 4. Seeing lines forming for pre-orders of a device is not something you often see, but it seems that Apple has created quite a bit of hype for their new device. Apple's site still says that pre-orders will ship on June 24th, so if you haven't gotten your order in, it would be wise to do it before the supply is gone. Have you pre-ordered an iPhone 4 this morning? Share your experiences with us!