It's definitely fair to call Emacs an IDE, once you learn all the stuff it can do to help you code. But anyway...
The compile command is useful for a few reasons. For example:
M-X compile <RET> gcc myprog.c <RET> (or C-c o)
If you do it this way, emacs will open a second window, which will display the compiling process and any errors. If there are any errors, you can use the C-` command, and emacs will automatically move the cursor to the place in the code where the error occurred.
Use the C-x 1 command to close the compiler window.
In languages like Haskell that have any interpreter shell, you can usually use the C-c C-l command, and it will load the file you are editing into the interpreter, and open up an interpreter shell within emacs itself.
To learn more about all the cool stuff Emacs can do, use the command C-h r.
(I'm using Emacs 24.2.1. You might be using version 23 which has less features.)