FileMaker has two Send Mail options, Client and SMTP. For Client you need to be using an actual application client, a web-based e-mail provider won't work.
Creating a utility layout to send mail via SMTP is not very difficult and pretty effective.
I will build that utility layout.
Seems like thats the way to go.
I'm thinking I'll create a user table with their email info that they can input once. That way, every time they run the script they will not need to input their email and password.
Will each user have their own e-mail settings, or is everyone sharing one set of credentials? If it's the former, it's a good idea to have a "Users" table with their info, otherwise you want to put the credentials in a single record utility table. On startup have a script load the appropriate credentials into global variables and reference those variables in the script step.