The most common variety of repair components are trademarked Helicoils; the hole is drilled and tapped oversize with a special tap and the Helicoil inserted with a special tool. Its driving tang is broken off and the repair is complete. The new threads will be stronger than the originals. A good bike shop should be able to make the repair easily and economically. The shop may possibly be able to provide a replacement pedal or you may have to buy a new pair.