I have insert my site in many directory but now I don't remember in which directories. Is there a way to know that ?
Try submitting to them again will let you know if the url already exists. Best way is to keep an excel of all your submissions, or if you work your way through lists at least make note of what page your up to.
yea best to keep a record you cant depend on submission received and approval emails either because a lot of directories don't send them
You should keep a record of your submissions. Try a tracking system like mine. For now, you can try "link:www.domain.com web directory" query in google or yahoo siteexplorer to find your backlinks from directories.
You can use Yahoo Site Explorer to check your back links: http://siteexplorer.search.yahoo.com/advsearch?p=http%3A%2F%2Fwww.mydomain.com%2F&bwm=i&bwmo=d&bwmf=u You only need to change mydomain.com with your actual domain name.
You could also check your emails, because more directories send confirmation emails when your link is accepted.