Looks good, although it would be helpful to know more about how this works before pushing us to create an account. Good luck!
That said, awesome app. It's certainly a problem I'm sure many are constantly faced with. (I know I am) My first impressions though include a lack of detailed info (how does it work?) compounded by the inconvenience of making an account for the site. (I still haven't registered)
Edit: As for a small change you can do right away, I feel like users would consider "John Doe" <jdoe@example.com> more intuitive than "Invite Name" <Invite Email>. (Consider making the name optional altogether or just having a more intuitive input method, like multiple <input> prompts)