As far as I know the only IDPA club in Oxford is The Izaak Walton League Tallawanda Chapter. The normally shoot on the 2nd Sunday of the month (except this month, it's the 3rd).
There is an IDPA shoot this Sunday at Tri-county Coon Hunters in Batesville, IN. A lot of the people who shoot Oxford shoot here too. They shoot 3rd Sunday of the month April - October. Registration starts at 9:00, shoot starts at 9:30.