Objective C is a special dialect of C that allows you to code for the Mac OS X and the iPhone.
It's very interesting to know that MinGW contains the GCC compiler that can compile Objective C code.
Using MinGW with MSYS I got to compile and run the following sample Hello World program saved as Hello.m:
int main( int argc, const char *argv )
printf( "hello world\n" );
All that you do is open MSYS and run the GCC compiler.