On my first web server (CentOS), when I edited my cron it opened up using nano. Unfortunately my second web server, again CentOS, opened the cron using vi. To setup nano as the default editor for your cron, you can do the following
Of course you could use any editor as your default, but I like nano.
You can do this once every session, or you can add it into your login script and you never need to type it in again.