[PHP] Email - format

[Sheni R. Meledath]

Hello:

Can any body provide me with a regular expression (as per the latest 
standards) to check the validity of an email address.

I am using some of the below formats. But these formats are not handling 
all the email addresses.

Format I:

ereg("^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$", 
$email)

Will not accept hyphen (-) in the email addresses.

Format II:

eregi("^[_\.0-9a-z-]+@([0-9a-z][0-9a-z-]+\.)+[a-z]{2,3}$",$email)

Will not accept domains like y.net.ye

Please suggest a regular expression which will reject only email addresses 
which are 100% invalid.

Sheni R Meledath
[EMAIL PROTECTED]