[snakes1100]

Typically in most ftp browsers, you can simply right click a file and click edit, the program will open the file in the default program that is set in its program options, typically as wally said that will be notepad, when your editing is done, click file at the top, then click save in the list, close the file and click ok in the ftp program so it re-uploads the file for you.

Some ftp browsers differ, some make you upload after the changes before closing the file after save, some like flashfxp make you close the file first, then click ok in the ftp browser.