http://www.snopes.com/inboxer/household/wd-40.asp
If you check out what Snopes.com has to say about this email, it turns out that it's about half true, which is far better than most viral emails. THe above link includes the manufacturer's culled list from the email supporting about half of the claimed uses; the others are not recommended. The fish oil part, of course, is bogus.
Steve