http://www.ee.surrey.ac.uk/Contrib/manx/famhist/genealgy/ldsfilms.htm
has a list of film numbers
The current IGI in my opinion needs a health warning - a considerable amount of the Manx records appear to be patron/Mormon baptism etc entries - these are in general WRONG - suggest that unless you can check with the submitter that you only believe what is in the transcriptions of the Parish registers (and even these sometimes need checking)