Hi McKid:
Without knowing too much about your college or particular situation, I would suggest that the ladies who are interested in being in a sorority start organizing themselves. Find out what each person is looking for in a sorority and start doing research on the various organizations out there. Most sororities are happy to send you at least some information via email or regular mail, and most nationals/regionally located sororities have a board member who is in charge of new chapter expansion. This person can assist you as well.
As someone who went through the new chapter founding process, I would stress that it is more important to find a sorority that meets what YOU are looking for, instead of just finding a sorority that is seeking to expand at your campus.
Good Luck!