Leaked training videos peg Lumia 920 as AT&T exclusive for six months, shows off City Lens, wireless charging

Itching for Nokia's latest piece of Windows Phone kit, but aren't ready to saddle up with Ma Bell? Get comfortable: according to a leaked AT&T training video, you'll have to wait six months for the Lumia 920's exclusivity contract to expire. The unofficial Windows Phone 8 flagship is due out next month, though mum's still the word on its actual ship date. The trio of videos also give AT&T employees a brief run down of Nokia City Lens, wireless charging and the handset's NFC features. If you simply can't wait until spring, Verizon and T-Mobile are serving up a pair of mid-range alternatives, the Lumia 820 and 822, respectively. Otherwise, head past the break to see the videos for yourself and test your patience.