Which is the best source to look for vacant seats other than hemp...thanks a lot.
I think you meant ERAS. Right now, almost all, if not all, ACGME-accredited programs only accept applications through ERAS. However, not all programs participate in the match i.e they make prematch offers. NRMP is used for the match and the subsequent SOAP which you can choose not to participate if you accept a prematch offer.
I believe ERAS or NRMP provides a list of unmatched programs at the beginning of SOAP.