I think you can invite her via facebook.
Have her go to the Glitch home page and sign up. Once she gets her letter you go to your home page here and see the area in brown, about seeing if any of your fb friends are waiting? Go on, do that thang. I'm not sure how it works but it seems that should piece it all together :)
pet pet, nibble nibble :P
Or, at least for the next few hours, if she has already signed up for an invite, she can use this page to get it sent (near) immediately: www.glitch.com/fans/