I know there's a form you can get from the Theta main site ... last time I looked there was a link with a blurb entitled "Do you know a young woman who would make a good Theta?" or something like that. All the forms and stuff are in Thetas online, you'll need your member number to get in.
Also, I think they sent out a rec form in the last magazine, or the one before that, you can check those.
Hope that helps.