New Yorkers observed that they weren’t able to obtain the iPhone from AT&T’s website last weekend, but as of today the phone is now available online. AT&T isn’t the only carrier under pressure with the amplified demands that smartphone owners are putting on wireless networks. Yesterday the Financial Times reported that O2, which also carries Apple’s iPhone, expressed regret to London smartphone owners after subscribers began complaining about the incapability to place phone calls occasionally during the second half of the year.