An issue with Wi-Fi connections is affecting iPhone 3G owners, according to forum discussions. Those with the problem cannot connect to Wi-Fi networks, regardless of signal strength. The originator of the forum topic notes that Wi-Fi may only work after a phone has been freshly rebooted. Alternately, multiple people have commented that while a connection may technically persist after a phone has been put to sleep and awakened, users may suddenly find themselves unable to receive data.
Other contributors to the topic suggest that the issue began only after they tried updating large applications from the App Store using Wi-Fi. The original iPhone and the recently-released iPhone 3GS do not appear to encountering difficulties. It is unclear whether it is hardware, software, settings or a combination of the three is causing the problem, as Apple has not issued a statement.