The Canadian Archives are in the process of putting their Attestation Papers from WW1 online. [Starting at the beginning of the alphabet? - BREW is there.] So-far there are over 350,000 records available.
There are already dozens of digital images of pages filled in by men who gave their places of birth as within the Isle of Man, dates of birth, next of kin with addresses often in the Isle of Man, and other details. There is a good search page at http://www.archives.ca/02/020106_e.html
Thanks to Keith Wright for finding this excellent resource!
Sue