Facebook is a cool place to interact and socialize with lot of friends. However, if for some reason you can want to delete Facebook account then follow the procedure below. Facebook by default provides you option to deactivate account (which is not actually deletion of an account).
Deactivate Facebook account
1. Goto Facebook.com & login into your account.
2. Click “Settings” link at the top.
3. Scroll down & click “deactivate” button next to deactivate account.
4. Fill the form & click “deactivate my account” button.

Please Note - Even after you deactivate, your friends can still invite you to events, tag you in photos, or ask you to join groups. For permanent removal of your Facebook account, follow the procedure below:
Delete Facebook account permanently
1. Goto Facebook.com & login into your account.
2. Click here to delete Facebook account webpage.
3. Click Submit & follow on-screen instructions.

Once account is deleted using above procedure, it canNOT be recovered in any case. So, be careful. Also See how to block Facebook website on the computer.

Thanks for these tips, I made two accounts and when facebook introduced vanity URL, my one account was able to get benefit from this offere, so I wanted to delete my othere account permanently.
wii facebook contact me when i have been permanantley deleted from facebook?