The new Apple iPhone went on sale in the US and several other countries this morning, but early reports of problems activating the device seem to be overshadowing its debut. You see, unlike with the first version, in-store activation is mandatory for the iPhone 3G as a measure to curb hacking – and protect both Apple and AT&T’s revenue.

But demand for the new iPhones is apparently so high that Apple’s activation servers actually crashed under the load, resulting in customers being sent home without activated iPhones. Even more frustrating, some customers upgrading from a first-gen device ended up with both their existing and newer iPhone bricked. As a result, people are being told to finish the activation process themselves by synching with iTunes later in the day.

Early setbacks aside, the second version of the iPhone is expected to have a stronger debut than its predecessor, as its being simultaneously rolled out in more than 20 countries around the globe.