FileID - Check file type/extension

Maybe sometime you've downloaded some file attachments from email or link provided by your friends and suddenly is does not have an extensions!!! So how to detect or check file extension? I just found these 2 useful softwares for you to grab:-

• http://dracuul.tripod.com/fileid/
• http://forum.abelhadigital.com/index.php?showtopic=440