A brief overview (Source: Nokia)

Widgets are small applications, based on standard web technologies, that typically serve as front ends to Web 2.0 services or internet content. Web designers and developers use widgets to make favourite internet experiences available from the S60 idle screen or Applications menu through single clicks or as read-only content on the home screen of the Nokia N97 mobile computer.

In just hours or days, using the web design skills you already have in creating HTML, CSS, or JavaScript™ code, you can provide mobile users with an engaging, easy-to-use interface to your web service. Keep in mind that, widgets offer the opportunity to create one-to-one relationships with your customers, because content served through a widget establishes a focus and level of trust that you can build on. When a widget interacts with information on a user’s device, it helps to reinforce that trust by presenting the most relevant content to the user.

The benefits of widgets don’t stop with ease of development and user engagement. Deployment is simple: Widgets can be distributed in the same way as any S60 application. The Ovi Store is the best option for reaching millions of Nokia users all over the world. To get your widgets distributed through the Ovi Store, sign up on the publish to Ovi website.

 

Some Suggested Web Resources 

Documents and examples »
Discussion Boards »
Wiki »
the technology available to WRT widgets »
Platform Services technology available to WRT widgets »
S60 3rd Edition, Feature Pack 2, S60 5th Edition, and Nokia N97 SDKs.
Forum Nokia Go to Market page »
Widgets for the S60 Platform E-learning

The Web Developer’s Library provides a comprehensive reference source for developers creating WRT widgets. 

don't forget... The Calling All Innovators contest is looking for both websites which are optimised for mobile browsing with Nokia devices, as well as web applications called WRT widgets for Nokia devices.