Amazon is planning to release a special software update that will add new features to existing Kindle devices. Starting today a "limited group" of users will have their Kindle devices updates to Firmware 2.5 while the rest will have to wait for an official release in May. Those selected merely have to have their Kindles turned on with the built-in wireless activated, the system will automatically download and apply the new changes.

The new features are significant and address the Kindle's weakness in organizing content with a new Collections system to better sub-divide titles. Other tweaks include more fonts and crisper text, pan and zoom controls for use with PDF documents, and the ability to lock your Kindle with a password.

Continuing to leverage the Kindle's wireless access, Amazon is also adding features for social networks. You'll be able to select specific passages from books you enjoy and share them using either your Facebook or Twitter account. Similarly you can also connect to see what members of the Kindle community have chosen as interesting book passages.

When it becomes available, Firmware 2.5 will be available for both the regular Kindle and the larger Kindle DX.