Does homers story of Trojan war have a historical basis?

It almost certainly does, though since the Trojan War occurred during the Bronze Age, when the lines between history and myth become blurred, it's difficult to say what the exact circumstances were. We do know there was a city of Troy (long though to be a myth in and of itself) and that Agamemnon and Menelaus were indeed kings of Mycenae and Sparta.

Aside from its depiction of Achilles as a sWord-for-hire, and Agamemnon as power hungry King bent on world domination, I think the movie Troy presents an interesting take on the Iliad story without any religious interference.