Updated: iPad Rush: CBS, ABC Create Special Stream Formats; Madison Ave. Scrambles

TV networks and advertisers have been rushing to get ready for the release of Apple’s iPad on Saturday and from the looks of it, they all wish they had a little more time. The WSJ has a pair of articles detailing the initial efforts of ABC (NYSE: DIS) and CBS (NYSE: CBS) to get free streaming streams of their respective primetime programs available for the device, while dozens of advertisers are excited by the potential of the iPad appears to present, but most haven’t been able to showcase the burst of creativity in time for the iPad’s debut.

Update: Disney unveiled a few more details about the wide range of iPad wonders it has prepared. iPad users will be able to watch 20 popular ABC series through a WiFi connection. The company makes a point of noting that this is the first time its ABC Player has been made available for a mobile device. The app will also allow iPad users to purchase downloads of episodes via the iTunes store. More on Disney’s other iPad plans here and on ABC’s iPad site.

Sidestepping the iTunes Store: Both ABC and CBS already make a large number of their shows available for ad-supported streaming on the web. So what’s the difference with the “iPad-specific” streams? Not much, it seems, according to this WSJ piece. Nevertheless, CBS Interactive’s Neil Ashe tells the Journal, it’s inspiring a much bigger push to make its shows more widely distributed. “We’re working very hard to make as much of it available as possible. Over time, it’ll be the same as online.”

While CBS will rely on viewers seeking out programs like Survivor on the iPad-version of its site ready to go for the weekend, ABC will be release a free app for the device that will mirror the ads and offerings on ABC.com, unidentified sources tell the WSJ. CBS has an iPhone app, but that only shows clips. NBC also makes shows available on its iPhone-enabled site, but the network doesn’t appear to be joining its two broadcast rivals in making an extra effort for the iPad. Either way, the intense interest ABC and CBS have getting their shows ready for the much-hyped device is matched only by their desire to avoid the iTunes Store, where Apple (NSDQ: AAPL) is struggling to sell 99-cent episodes for download-to-own.

Advertisers prep iPad-ready ads, but creativity waits: For marketers, the iPad represents a two steps forward, one step back in the advancement of mobile advertising. The wider canvas of the larger mobile screen when compared to the iPhone promises to allow for greater creativity. But the constraints of working on the new system and the absence of the popular Adobe (NSDQ: ADBE) Flash program for animated images, represents a significant hurdle to overcome. The WSJ details Buick’s problems in trying to use a Flash-based campaign on the WSJ app. The carmaker hoped to send users interested in clicking on Buick ads for the midsized LaCrosse sedan to its Buick.com site, but since it features Flash, users would see a lot of empty white space where the multimedia content is situated. When it thought of sending users to its mobile wap site, which doesn’t have Flash, the site looked too shrunken on the iPad. “It was not pretty,” says Pamela Neville, a manager at Digitas, which created the ads.

But marketers are willing to make the effort for now, in hopes that they’ll be better able to figure out new ways of advertising on the iPad, assuming the device does take off.