Holy moly...Greek life at Penn State is huge!!!
Especially compared to UNC Greensboro, which is pretty small compared to its southern neighbors.
Anyway...I think you'll find that a lot of sororities are based on Christian ideals. In our creed, our duty to God is mentioned twice. We also have some very religious sisters who further explore their faith through Greek bible studies.
Then, too, that's not to say that everyone is extremely Christian, either...we have a sister who is Jewish, as well as several who are what would probably classify as "open-minded."
However, the religious issue isn't really an issue...we all just do what we can to respect each other's spirituality. Some even grow more deeply spiritual as a result of joining the sorority.
That was a little bit of a ramble...I just wanted to say that being in a sorority, at least in my experience, doesn't have an adverse effect on your religion. In some cases, being in a sorority can help strengthen it. So don't worry too much about religion keeping you from enjoying Greek life...as important as it is to you, you'll find somewhere you can feel comfortable. Good luck!!!