If I were sending a c.v. by email, I would write a covering letter (a proper letter) in Word -
Dear Mr Smith.... Yours sincerely, craftypig), saying that you enclose your c.v. and a paragraph about why the job interests you - just as if you were sending the application by post.
The covering email (to which the c.v. and letter are attached) then would say:
Dear Mr Smith (or Dear Sirs, if no name is given), please find attached my letter of application and c.v. for the post of ****. I look forward to hearing from you in due course. yours sincerely, craftypig.
It's not standard email format, but it's polite.