Substitution and checking expression

Hi,

I have a flash movie that calls a PHP script to send an email. The problem is that sometimes the variable comes like this: "Email:joe@domain.com"

How can I check and chop the "Email:" part of the variable?

And how do I remove any trailing and ending spaces after?

And - sorry for asking so many questions - do I exit the script if the result variable is null?

Kind regards,

Kepler