You can edit your Friends list at the following page:
You can remove a listed friend by checking the "Delete?" box before saving your changes. Many of the clients also allow you to add/remove friends. If you have not yet downloaded a client you may do so at http://www.livejournal.com/download/ .
To add friends and set up foreground and background colors, scroll down to the section of the page labeled "Add Friends." You can also add users to your friends list by visiting their user info pages and using the "Add Friend" button on the toolbar, as described in http://www.livejournal.com/support/faqbrowse.bml?faqid=41 .
Usernames that appear in bold text when you view your own user info page or someone else's mean that you have added that person to your Friends list. Additionally, when you view the "Friend of" list on your user info page, usernames that do not appear in bold print are those of people who have added you to their Friends list, but whom you have not added back.
Usernames that are struck through indicate a user on your Friends list that has either deleted their journal, or had it suspended.
You have the ability to hide your "Friend of" list by checking the "Hide "Friend of" list" option in your Personal Info page (http://www.livejournal.com/editinfo.bml). This will also hide your "Member of" list. You can't, at this time, hide those users you list as a friend, or the list of communities you have posting access to.
For information on dividing your friends into groups, see http://www.livejournal.com/support/faqbrowse.bml?faqid=102 .