Zynga, maker of the popular Facebook game FrontierVille has announced that they are now using an in-game cameo to promote Johnny Depp’s upcoming game Rango which hits theaters this coming weekend.

Starting today, players are told to find Rango. Players must ask their friends for 10 water buckets and then view a trailer of the movie, at which point they will receive a Rango statue to put on their homestead.

The promotion of movies isn’t a new gesture on the part of Zynga, they have also promoted The Green Hornet and Megamind but at least this time the movie they are promoting fits in a little better with the time period of the games theme.

Promoting products via social media games is becoming increasing more lucrative, with 19 million people actively playing FrontierVille, an estimated 9 million people took part in the Megamind promotion alone, a number equal or greater to the number of individuals who would have seen a commercial for the movie during primetime broadcast of a popular TV show.

Also, since prizes are awarded, consumers become more vested in the process, thereby creating a more engaged audience for the movies promotional ties to Zynga.

Of course like any new type of campaign, it’s still unclear what type of conversion numbers such type of promos have for bringing audiences to the theater.