The popular mobile browser Opera today launched a software developers kit (SDK) for widgets. While rival Apple’s iPhone SDK requires that applications be distributed exclusively through the still-unlaunched iPhone App Store, pay a $99 application fee and wait – Opera SDK built widgets appear to be much more open and free.

Opera’s widgets will be able to run on the company’s wildly popular mobile browser, Opera Mini excluded, the desktop version of Opera, the Nintendo Wii and any other devices that run Opera 9.5. We covered the launch of 9.5 here.

How important is this battle, not just between Opera and Apple, but between a wide range of mobile platforms? As Josh Catone wrote here this morning, the key to beating Google may be beating Google on the mobile platform. This Opera SDK can also be seen in that light.

Opera differentiates itself by being highly standards compliant, cross platform and feature-rich. While not nearly as popular inside the US as it is internationally, the company’s fans are many and outspoken.

Can freely developed and distributed widgets from Opera challenge the awesome wow-power of iPhone apps? As the initial shock of the iPhone interface wears off and an increasing number of rival handsets begin offering similar functionality, that may be possible. The delays in opening the iPhone App Store have already begun to frustrate developers, but the expected release of a 3G iPhone and a big subsidy driven price drop may extend Apple’s lead by the time the App Store launches.

Below is a video released by Opera explaining the SDK. To see the video in greater detail click menu and select fullscreen.

Opera Widgets SDK Guided Tour

by operasoftware