I have downloaded the omniORB4.1.6 pre-compiled with msvc10. I have python 2.7 and everything seems to work fine. I want to know how i can tell my omniidl to use my python 2.6 installation instead of 2.7. Can anyone help me? Thanks.
you can't and shouldn't.  it is compiled specifically for 2.7.  that's why "2.7" appears in the download file name.
if you want to use a different python, download the source package and build it yourself.
Changing python from 2.7 to 2.6 for omniidl