Here's a list of websites where you can tap into the Unity development community to find answers and to ask questions. Please remember to be courteous and respectful of more experienced developers' time. As with any online forum, be sure to search existing content for an answer before you ask a question.
Unity Manual: When you're new to a technology and you ask naive or poorly researched questions, you may hear "RTFM" a lot, which stands for "would you please be so kind as to review the product manual?" Well, here's the link to the product manual, which covers both beginner and advanced topics, including examples on writing your own custom Shaders:
http://unity3d.com/support/documentation/Manual/index.html
Google: A search engine should be the first place you look for answers. If the solution is plainly available with a simple query, you'll quickly exhaust the goodwill of the real-life people you petition for help online:
Unity Answers: This Unity sub-domain bills itself as "The best place to ask and answer questions about development with Unity", and it's not lying. Many of your Google searches will lead you here:
Internet Relay Chat (IRC) : This is an old-school chat system. You can download an IRC client to reach one of its many servers. IRC users split themselves into channels by topic. The very best channel available for Unity discussion is #unity3d on the server group irc.freenode.net. Wikipedia hosts this list of IRC client programs:
http://en.wikipedia.org/wiki/Comparison_of_Internet_Relay_Chat_clients
Unity 3D Tutorials: The creators of Unity host a growing number of tutorials on the program's official site:
http://unity3d.com/learn/tutorials/modules
YouTube: The Internet's most popular video sharing site has tons of Unity 3D tutorials. Just search "Unity 3D" to get started:
Twitter: The best place to get up-to-the-minute news and information about practically everything is on Twitter. Follow as many Unity developers as you can find, and keep a watch on the #unity3D hash tag to become the smartest kid on your block. Twitter: it's not just about what your friends are having for lunch:
Unify Community Wiki: This is an excellent Unity resource where developers can help each other out. I've linked specifically to an excellent page outlining the differences and uses of various Collections (Arrays, Lists, Hashtables, among others), which was very helpful to me.
http://wiki.unity3d.com/index.php?title=Which_Kind_Of_Array_Or_Collection_Should_I_Use?