Using TextWrangler to edit files over FTP/SFTP
First, from the File menu select Open from FTP/SFTP Server...
Then, put in the information for the Dreamhack (or other server) you are hosting on. For dreamhacks, the server name is ssh-hack.dreamwidth.net and the username is your hack username, always in the form of dh-USERNAME, and you should know your password.
Then, you'll be able to browse and find whatever file you want to edit like normal.