301 and different domains and directories on one host

how do you do a 301 redirection for different domains on the same host

[jaidai]

I have 3 different urls that will be used for 3 different sites. I have set up the sites in different subdomains on my hosting service. I have one hosting plan. I need to set the urls using 301 redirection to the different subdomains. does anyone know how to do this?

[Robert Charlton]

Here's my learning curve on this one....

Pointing multiple domain names to main site without mirrors
How to do this without hosting them separately and using 301s?
[webmasterworld.com...]

Though alternate redirect types were suggested, at this point everyone concurs that 301s are the way to go.