Does Visual Voicemail support the Spanish Language?

No.
There are no Spanish Language prompts in Spanish for Visual Voicemail.

Is Spanish a language I may select for Sprint Navigation?

Yes.
Spanish is a setting for sprint navigation.
The turn-by-turn instructions will be spoken in Spanish.

Instinct How To Videos: The Samsung Instinct offers sixteen How To Videos which are linked from the Web Home Page on the device, and available for customers to view.