Bulk converting MSG files into HTM files

I am looking for a way to convert MSG files saved to hard disk and network drives into HTM files. I am doing some data mining for To:,From:, Subject:and Received:, on saved emails. This can be done easiliy on the files saved as HTM, but on the MSG files I am unable to read the header, just the body of the note which is not the info required. I can open and save each file as HTM, but there are hundreds so one by one is not a real option. Is anyone aware of any methods or software that can do this task as bulk. Regards Bill