I've been sending out a ton of resume's lately...most want them e-mailed and I just sent them as a word attachment. I got a reply from 3 or 4 asking to fax, put it in the body or snail mail it to them.
I'd say attach it to begin with and put in the body of the e-mail "I'm attaching bla bla bla". If they want it different, they'll let ya know.
-mini
*unless they stated otherwise...then do what they say
PS When I was on the other side and doing the hiring, I preferred them to be attached. Long winded e-mails usually got lost in my mind somewhere and yawn'd me off... ...If that helps.