1. Microsoft ASP.NET Forums
Microsoft ASP.NET Forums
http://forums.asp.net

2. Sun Forums
Sun Developer Network Forums
http://forum.java.sun.com/index.jspa

3. Mozilla Development Forums
Most forums are in pairs of a newsgroup and a mailing list. Each one mirrors its mate: posts in one newsgroup will show up in its corresponding mailing list, and vice versa.
http://www.mozilla.org/community/developer-forums~

4. MSDN
MSDN Forums
http://forums.microsoft.com/MSDN/default.aspx?Sit~

5. Forums.HostMySite.com
HostMySite Forums
http://forums.hostmysite.com

6. Forums eBay Developers Program
Welcome to the Developer Forums, a place for developers to share knowledge and ask questions about building applications using eBay Web Services.
http://developer.ebay.com/community/forums

7. Joomla! Community Forum
...because open source matters.
http://forum.joomla.org/viewforum.php?f=126

8. Amazon Web Services Developer Connection : Forums
Welcome to the Amazon Web Services Discussion Forums. Post your questions and feedback to these forums to help accelerate your development efforts and to engage with the AWS community. Use the RSS feeds and e-mail watches to stay in tune with the latest conversation for services of interest to you.
http://developer.amazonwebservices.com/connect/fo~

9. Webmaster Forums - Powered by vBulletin
Large discussion forum for webmasters and web developers
http://developers.evrsoft.com/forum

10. Oracle Forums
Oracle Forums - Welcome to our online community
http://forums.oracle.com/forums/categoryHome.jspa~

11. NVIDIA Developer Forums
NVIDIA Developer Forums
http://developer.nvidia.com/forums/index.php

12. XDA developers forums
Community of XDA developers for programming and modding of PDA Cellphone hybrids.
http://forum.xda-developers.com

13. Code Guru forum
Hard hitting articles, dicussions, resources, and more all focusing for real developers in the real world.
http://www.codeguru.com/forum

14. Facebook Platform Developer Forum
Facebook Platform Developer Forum
http://forum.developers.facebook.com

15. Apple Developer Forums
Apple does not provide online support to Developers in Apple Discussions. Apple Discussions Community members are welcome to assist each other.
http://discussions.apple.com/category.jspa?catego~