This is a copy of a post I originally had in Codecademy Forums years ago.
I thought I would post it again so people can benefit from the linked material; as it was made so long ago CC has since made some of the courses listed such as SQL and Java but for completeness I will leave these sections in so people have additional material they can use.
If you use any other good sites add them to the list, this post is a
wiki so click on the little green pencil in the top right to add to the list.
This is a great list of resources for learning languages we don't (yet!) teach, compiled originally by Patrick. Have others? Post them below!
C++ Tutorial from cplusplus.com
C and C++ Tutorials from cprogramming.com
Learn C the Hard Way
TheNewBoston's C++ Tutorials
Learn C interactive tutorial
Microsoft Developer Network (MSDN) C# Tutorials
MSDN Channel 9 C# Fundamentals Tutorials
C# Station Tutorial
Objective-C (iOS and Mac)
Objective-C from Cocoa Dev Central
Apple's Objective-C intro (you'll need an Apple Developer account, it's free)
Stanford CS193P Look under "more from Stanford" for iOS 5 updated versions. Also covers MVC basics that some have expressed interest in.
TheNewBoston's Objective-C Tutorials
Learn You A Haskell
Stanford CS106A Awesome class. It covers Java but more importantly it covers program design theory that many people have asked for. It can be followed up with CS106B and CS107 also available on that website, for more theory combined with (non-Java) practical.
TheNewBoston's Java Tutorials
Oracle's Java Tutorials
Practice-it Java practice
Now on Codecademy!
PHP Bounce (Interactive in the vein of Codecademy)
TheNewBoston's PHP Tutorials
MSDN Channel 9 VB Fundamentals Tutorials
Stanford's Introduction to Databases via Coursera
SQL The Hard Way
Eherrera Markdown Tutorial
Agea Markdown Tutorial
JacobSwain Markdown Tutorial
Programr (too many to list)
CodingBat (Java and Python)
Marakana Bookshelf (too much to list)
Marakana's Youtube channel (more advanced but great, too much to list)
The New Boston
Free books list on GitHub
A quick shout out to those who contributed the original links. Thanks guys.