Steve Jobs said the MacBook Air would be available in two weeks.  While it’s not in anyone’s hands, it has shipped.The company’s newest laptop, which CEO Steve Jobs called the “world’s thinnest” computer when he unveiled it two weeks ago at San Francisco’s Macworld, is shipping as of today, Apple said. The 3-lb. portable, which retails for $1,799 in its base configuration with a 1.6-GHz IntelCore 2 Duo processor, 2GB of memory and a 13.3-in. LED-backlit display, is also supposed to be available at retail,