There is good advice posted at:

http://www.gov.im/mnh/heritage/library/publicinfo/familyhistory.xml

http://genealogy.about.com/cs/isleofmangenealogy/

http://www.isle-of-man.com/interests/genealogy/sources.htm

http://www.isle-of-man.com/manxnotebook/famhist/genealgy/intro.htm

and heaps of relevant information at:
www.lawsons.ca

If you hit a "brick wall" use this bulletin board to seek advice, making sure you disclose much of the information discovered.