Here’s a simple windows compatible command line utility written by Brandon Zehm by which you can send mail.
It include some arguments like from,send, smtp username and password,subject and body. You can even attach file with the mails and also in HTML form.
So, you can embed this utility with your application and hence you can add E-mail feature for feedback or other purposes.
It works with Gmail and also with personal mail domain. Remember that you can use this for yahoo only if you are in paid version of it as yahoo doesn’t offer free smtp authentication in applications..
Click on this LINK to download the utility..
It also contains all the help files from where you can take the reference for syntax..
Good luck…