Ok, i have done a rebuild, this is the log
Project   : OGRE_Sample
Compiler  : GNU GCC Compiler (called directly)
Directory : C:\Documents and Settings\Ugo\Documenti\AVIV\OGREE\CodeBlocks\Ogre Tutorial\
--------------------------------------------------------------------------------
Switching to target: Release
mingw32-g++.exe   -Lc:\OgreSDK\lib -Lc:\OgreSDK\lib\opt\release  -LC:\Programmi\CodeBlocks\lib -LC:\Programmi\CodeBlocks\DevPacks\lib -o "OGRE sample.exe"     -Wl,--enable-runtime-pseudo-reloc  -lmingw32   -luser32 -lkernel32 -lgdi32 -lopengl32 -lOgreMain 
C:\Programmi\CodeBlocks\lib/libmingw32.a(main.o):main.c:(.text+0x106): undefined reference to `WinMain@16'
collect2: ld returned 1 exit status
Process terminated with status 1 (0 minutes, 0 seconds)
0 errors, 0 warnings
 
It's the same. For accuracy, i have done New Projects->Ogre Application. The variable $OGRE_HOME is set up on c:\OgreSDK where there are my include and my lib.
Any idea?
Thank you.