Note: You MUST have an Apollo Temple in your city before you may purchase an Apollo House.
Strategy
Offensive
It is nearly impossible to destroy a building surrounded with Apollo houses. Destroy them before attempting to destroy the building. Ares' Battle Ram ability, Artemis's multi-shot or Hera's Wrath are all good for this.
Destroying the Apollo Temple will destroy all Apollo houses. If possible, destroy the Temple as soon as you can.
Defensive
This house is incredibly powerful, especially when upgraded. Buy several and place them around your most important buildings.