Editing published stuff

Logged in to the back end as an admin, Manage/Posts/ then click on the title of the post you want to edit…

Depending on the template, you could log into the front as a member using your admin credentials and a little “Edit This” icon or link will magicliciously appear, usually in the post meta area (author name, post date stuff)

http://codex.wordpress.org/Administration_Panels#Manage_-_Change_your_content

Sure thing.