CodeProject: Free and open source code exchange community is a community website composed of software developers and designers to share free open source programming codes, where users can learn, share, and discuss topics related to software programming.
SourceForge: The world's largest open source software development platform and repository. The purpose of the website is to provide a storage, collaboration and publishing platform for open source software. SourceForge has a lot of very good open source software.
StackOverflow: A question and answer site for program-related IT technologies. Users can submit questions for free on the site, browse questions, index relevant content, and use simple HTML when creating the home page.