How to set up ssh so you aren't asked for a password

You can create a RSA authentication key to be able to log into a remote site from your account, without having to type your password.

Note that once you've set this up, if an intruder breaks into your account/site, they are given access to the site you are allowed in without a password, too! For this reason, this should never be done from root.

Run ssh-keygen(1) on your machine, and just hit enter when asked for a password.
This will generate both a private and a public key. With older SSH versions, they will be stored in ~/.ssh/identity and ~/.ssh/identity.pub; with newer ones, they will be stored in ~/.ssh/id_rsa and ~/.ssh/id_rsa.pub.
Next, add the contents of the public key file into ~/.ssh/authorized_keys on the remote site (the file should be mode 600).
If you are a developer and you want to access debian.org systems with such a key, it's possible to have the developer database propagate your key to all of the debian.org machines. See the LDAP gateway documentation.

You should then be able to use ssh to log in to the remote server without being asked for a password.

Important: Note that everyone that has read access to the private key file can use it to have the same passwordless access to the remote site. This includes any person that has root access to your local machine. Therefore it's strongly recommended that you use a passphrase for your private key if you are not the only root on your machine. You can use ssh-agent(1) and ssh-add(1) to type your passphrase only once for all uses of a specific key in a session. You can automatically load all your keys in the agent by adding the following lines to your ~/.xsession file:

      # if use-ssh-agent is specified in /etc/X11/Xsession.options
      # (this is the default) then you need only the second line
      # eval ssh-agent
      ssh-add <filename-of-ssh-key>

The ssh-askpass package must be installed in order to run ssh-add without a terminal.