Override 'From' email address and name

Hi,

Thanks for the great module!

I have created a simple module where editors can send emails via the admin interface using their email address and name, but when it's sent the email uses the email address and name set under the SMTP configuration page. I'm wondering what is the easiest way to override this (the email addresses are all valid addresses on the same domain). So I'm basically asking if there is any way to use multiple 'from addresses' for different users?

Thanks!