gtkmm on Windows XP

[Sergio Perticone <g4ll0ws gmail com>]

I've installed Dev-C++ (under C:\Dev-CPP) and Gtk+ & GTKmm (under C:\Gtk+).

Well, when I run "pkg-config --cflags gtkmm-2.4" I get:
"
Package gtkmm-2.4 was not found in the pkg-config search path.
Perhaps you should add the directory containing `gtkmm-2.4.pc'
to the PKG_CONFIG_PATH environment variable
No package 'gtkmm-2.4' found
"

How I can set PKG_CONFIG_PATH?

Thanks,

s.