Flash email through php - cross domain!?

Many of you know these usefull PHP scripts together with a form in Flash. Right? My question is, however, if it is possible that the script is located on another server/domain?

I am building a flash website for a friend without PHP rights on his server. I was thinking what if I put the php script on my own server/domain. Is this even possible or do I have to some ‘special’ tricks to get this method to work?