How to place a Signup form on Facebook and Twitter?


After looking over the forums, I am needing a way to create and put a Signup form on my Facebook and Twitter. I am using it to gain new subscribers, by offering discount promotion for signing up.

Currently, I am using the Plus version of phpList Hosted.

Is it possible to do this? with commercial services, it places a link or button on the Facebook page to signup/ subscribe

If anyone been able to do this?

Best regards,