Mozilla Developer Center - Organized by topics provides documentation about extensions, themes, applications, frameworks and technologies. Mozdev - Provides free project hosting and development tools for extensions. Includes bug tracking, CVS repositories, mailing lists, newsgroups and download mirrors. Spket IDE - IDE for JavaScript and XML development. Offers many features to increase the productivity for Mozilla Extensions developers. BabelZilla - International community of translators for Mozilla applications. Includes a system to allow online translations, a list of common extensions terms and tutorials for extension localization in many languages. Extension Wizard - Generates a zip file with an extension skeleton for Firefox and Thunderbird. So You Want To Sign Your XPI Package? - Step by step explanation on how to sign an XPI package in Unix type systems. Firefox Toolbar Tutorial - Overview about the tools required to create an extension and details on how toolbars are created. Software is Hard - Tutorials and comments about developing and extending Firebug. XPISigner - Command-line utility to simplify the process of signing extensions. All Interfaces - List of interfaces with filtering tools, stripped code and highlighted comments. MozillaZine Forums : Extensions and Themes - Discussion board about releases and development of extensions and themes. How to hack extensions to make them compatible with SeaMonkey - Provides a template install script and describe possibles problems when porting extensions. Think Global, Make Locales! - Babelzilla blog, with tutorials and news about the Mozilla community and localizations. Robert's talk - How to develop a Firefox extension - Covers some of the required steps to start a Mozilla extension. Mozilla Extension Generator - Python script to write extensions structures. Mozilla Add-ons Blog - News and post for add-on developers.