If you've lived in PA for more than 10 years, there is a waiver you can sign and submit to the school along with your other clearances. If you have not lived in PA for more than 10 years, you must be fingerprinted. If you do need fingerprints, you first must register here: 3MCogent
If you cannot use the waiver, AND you've been fingerprinted in the past, you must provide the "unofficial copy" of your FBI clearance to the school - that is only good for 5 years, so you will need to be fingerprinted again 5 years from that date. IF you are unable to locate your "unofficial copy" you MUST be fingerprinted again.
In order to volunteer at any Pennsylvania school while children are present, you must complete three background checks: two from PA, one FBI (including fingerprinting). For the PA clearances, if you select "volunteer" they will be free. There is a cost for the fingerprinting. For some of these, you will need to gather information about prior residences, people with whom you shared those residences with, etc. So be prepared for those questions - and you can save the application and return to it. Here is the FAQ sheet from the Commonwealth.
There are two background checks administered by Pennsylvania. One is through the PA State Police, the other through the PA Department of Human Services. If you are an educator your clearance from the PA Department of Education is virtually identical and acceptable.
You need to print the State Police Results as once it's closed, you'll have no further access to the results, and you need the info for the second clearance:
Additional information for clearances and access to the second clearance can be found here:
To report suspected child abuse go to www.compass.state.pa.us/cwis or call 1-800-932-0313.