PSU has a great Greek Life website:
http://www.greeks.psu.edu/ and a nice Panhellenic website:
http://www.greeks.psu.edu/panhellenic/.
They have 21 sororities:
Alpha Chi Omega
Alpha Omicron Pi
Alpha Delta Pi
Alpha Phi
Alpha Xi Delta
Alpha Sigma Alpha
Chi Omega
Delta Delta Delta
Delta Gamma
Delta Zeta
Gamma Phi Beta
Lambda Delta Omega
Kappa Alpha Theta
Kappa Delta
Kappa Kappa Gamma
Phi Mu
Pi Beta Phi
Sigma Delta Tau
Sigma Sigma Sigma
Sigma Kappa
Zeta Tau Alpha
I recommend that you go through Formal Recruitment as a freshman, it opens up your options and unlike informal recruitment, gives you an opportunity to learn about all the chapters.
Good Luck!