Valid Email function

1

I have a php function to validate an email address in my flash form, but there is one problem.

The function valid_email only works if your email address is something like:

test@test.com

But it comes up invalid email if your address is:

**test@test.co.uk **
[color=#006699]test@test-test.com[/color]

Does anyone know how to change the function so you can have email address like:

**test@test.co.uk **
[u][color=#006699]test@test-test.co.uk[/color][/u]

as well as [u][color=#006699]test@test.com[/color][/u].

Here is the function from the tutorial:

 function valid_email($email) 
{ 
// check if email is valid 
if( !eregi("^[a-z0-9]+([_\\.-][a-z0-9]+)*" 
."@([a-z0-9]+([\.-][a-z0-9]+))*$",$email, $regs)) 
{ 
	 return false; 
} else if( gethostbyname($regs[2]) == $regs[2] ) 
{ 
	 // if host is invalid 
	 return false; 
} else { 
	 return true; 
} 
}