I've been searching for something like FireFTP for a long time. This plug-in for the Firefox browser brings a useful, interactive FTP client into the browser. You can access from the tools menu and, optionally, configure it for all ftp links. Drag and drop files, store accounts to connect to and generally make dealing with ftp file transfers much easier without needing a separate ftp client outside the browser.
You can
download FireFTP from Mozilla's plug-in site.