Macworld is Apple Inc.’s four-day trade show, focusing on Apple hardware and software products and innovations.  Topics on the 2011 call for submissions include usage and skill development of Mac OS, iPad, and iPhone; applications; system troubleshooting; graphic and web design; publishing workflow; music and audio production and performance; digital photography and video; enterprise computing and IT; Mac OS X administration and server usage; K-12 and higher education; small business; and networking.  The conference will also include a Mobile Apps Showcase.