The following University networks particularly welcome the involvement of businesses:

If you cannot find the networks that you want in the above list, please email business@admin.cam.ac.uk, being as specific as possible about your requirements.

Finally, a full list of all talks given at the University of Cambridge can be found at talks.cam.  If you create your own account on this site, you can receive emails about talks you are interested in and upload details to your electronic calendar.