A password on an Apache SSL certificate means that a restart of Apache or a cold boot of the system requires user intervention which outweighs the cost of not having the password.

On an existing certificate key file, you can remove the SSL certificate password by doing the following:

// backup your current key first
# openssl rsa -in domain.com.key -out domain.com.key.nopass

Now just replace domain.com.key with domain.com.key.nopass and restart Apache.