Get ready for Steve Jobs lookalikes sporting blue jeans and his trademark St. Croix mock black turtleneck shirt swarming Silicon Valley. \u00a0\n\tSt. Croix says sales of its popular cotton pullover have doubled since Steve Jobs\u2019 passing last week. For every black mock sold, St. Croix plans to donate $20 to the ongoing fight against cancer.\n\n\tMore than just a shirt, Jobs\u2019 black turtleneck set the tone for \u00a0casual fashion \u00a0at many Silicon Valley tech companies. From the wind-blown hair of Google CEO Larry Page to the T-shirt-wearing Mark Zuckerberg of Facebook, top Silicon Valley executives hope to tap the comfortably creative genius of Jobs. (The most notable exception, of course, is Oracle\u2019s suit-wearing Larry Ellison.)\nSlideshow: If Corporations Were People\u2026\n\tThe turtleneck is just the tip of the iceberg when sizing up Jobs\u2019 influence on Silicon Valley culture, which is probably why Silicon Valley is still in a funk this week.\n\tTo be fair, Jobs, too, tapped the creative energy of Silicon Valley, with its liberal colleges, diverse culture and futuristic thinking. It\u2019s no surprise that Jobs gave his famous commencement speech at Stanford University in 2005. Also, one of his last acts was to propose plans to the city council of Cupertino to build a Silicon Valley landmark office building that looks \u201ca little like a spaceship has landed,\u201d he said.\n\tJobs wore his mock black turtleneck at every recent major Apple announcement and product launch. The shirt has become a symbol of creativity and success. Now everyone wants to be Steve Jobs.\n\tBut where, exactly, will one be wearing this shirt? At Silicon Valley trade shows? Inside Silicon Valley cubicles? Standing in line at Silicon Valley Apple Stores for the iPhone 4S? It would be similar to a few years ago when golfers wore Tiger Woods\u2019 trademark red shirt and black pants on golf courses. It\u2019s a little creepy.\n\tDemand has been so high for St. Croix Style 1990 classic mock black turtleneck that the apparel retailer has sold out of them. St. Croix says it is now accepting orders for this item to be shipped by October 28. Just in time for Halloween. Now that\u2019s really creepy.