Yeah,
go to cnet or zdnet, go to the download section,
download a keylogger
insert it as an attachment in email
Send the email.
But, wouldn't it be quicker to just download it on the computer you want it on? (since it has to open that email anyway?)
Ohhhhhhhhh, I get it... you want to do this without someone detecting they're getting a keylogger....
you're a bad person.