validate email with yahoo.com isp

I have this code:
if ( !strcmp($Email,$Email2) && (!eregi("^[_\.0-9a-z-]+@([0-9a-z][0-9a-z-]+\.)+[a-z]{2,4}$", $Email) || db_arr("SELECT ID FROM users WHERE UPPER(email) = UPPER('$Email')")) )


I want validation only for yahoo.com addresses. Regards

'/[_\.0-9a-z-]+@yahoo\.com/'

I think.. not too good at regex :rolleyes:

mmm why not work?