Take a look at the State Treasury website first. Often you find items there that have been unclaimed. I recently made a transfer there and it only requires a few papers.
The PA website and links to those of other states, Puerto Rico and Canada may be found at www.naupa.org.
While a service such as this may be legitimate, the states generally require some affirmative documentation that you are entitled to recover the funds, plus a death certificate and account documentation if you can find it.
The foregoing is not legal advice nor is it in any manner whatsoever meant to create or impute an attorney/client relationship.