htm plain & plain text e-mails

[lomokev]

i dont no wheter this is the right place to post this? it's kind of html related

how do you send a html mail that has a plan text alternative so that if the receiver can't see html e-mails then they will se the plain text alternative is that possible?

+ is there application that lets you do this? MAC or PC any suggestions? because when i have sent html mails in the past i have done it with a php script

[Gibberish]

blueHornet does this. I don't know what else is out there because that is the only service I have used for it.