The easiest way to find a large number of Facebook friends at once is through the website's e-mail finder. When you enter your e-mail information, Facebook is able to scan your address book for contacts who also have a Facebook profile. You can send a friend request to some or all of your e-mail contacts at the same time. After your request is sent, it is up to the contact to accept or reject a Facebook friendship with you.
Click on the "Friends" icon under your profile thumbnail on the Facebook home page.
Click on the "Find Friends" link located next to your e-mail service provider. If you do not see your provider listed, click "Other Email Service" at the bottom of the page.
Enter your e-mail address and the password associated with it and click "Find Friends."
Review the list of your contacts that have a Facebook account. Check the box next to any person that you want to friend on Facebook and click "Add as Friends." A friend request will be sent to each contact you selected.