In order to have a verizon.net username and password, you have to have a Verizon Online account for internet access. (FiOS, DSL, dial) If you don't have a VOL account (if you are a wireless-only customer) then you don't have access to the verizon.net email servers.
If you are a VOL customer, then your username and password should be what ever you use to log in at http://www.verizon.net
If you are not a VOL customer, then you either need to become one, or find a different outgoing server to use. (I recommend getting a free Gmail account and using their SMTP server.)
Hope this helps!