I'm going to start the ball rolling on a set of useful external programming resources. If you know of any excellent tutorials or resources, post them here and I'll add them to the list.

General Language Resources
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C Language
The C Book - GBDirect Publications
A digital copy of a book that extensively introduces and covers the C language which was originally published in 1991.
C++ Language
GameDev C++ Workshop - GameDev.Net
An extremely comprehensive set of workshops teaching C++ ranging from pure beginner through to advanced levels.
CodeGuru: Visual C++/C++ - CodeGuru.com
A collection of articles dealing with the basics along with various algorithms and additional libraries for C++.
C# Language
C# Workshop - GameDev.Net
An extremely comprehensive set of workshops teaching C# ranging from pure beginner through to advanced levels.
CodeGuru: .NET / C# - CodeGuru.com
A collection of articles dealing with the basics along with various algorithms and additional libraries for C#.
Online Code Repositories
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Krugle
An online code search engine. When you search for an entry, it scans every entry in its database and returns the results as code snippets.
Google Code
An online database dealing with primarily Google-based API resources, however with the addition of many open-source code projects.
Online Publications
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Safari Books Online
An extremely vast repository of published technical manual books that have been digitized and stored online. Very useful resource, however it requires paying a subscription fee ($23 US/month, $253 US/year). A free trial is also available.
The Pragmatic Bookshelf
A large collection of eBooks distributed in the PDF format. Each book must be purchased separately, (avg $20 US each).