Viva Piñata on PSP? Never Released.

No Viva Piñata game exists for PSP. The franchise (Rare / Microsoft) launched on:

• Xbox 360: Viva Piñata (2006), Viva Piñata: Trouble in Paradise (2008).
• PC (Games for Windows Live): Viva Piñata (2007).
• Nintendo DS: Viva Piñata: Pocket Paradise (2008) — This is the handheld version.

Pocket Paradise (DS) vs Console

• Full garden sim, stylus controls, all piñatas, co-op via local wireless.
• Graphics scaled down, but gameplay intact.
• Often cheaper than console versions.

If you have a DS/3DS, Pocket Paradise is the way to play Viva Piñata portable. PSP owners: remote play PS3 version? Not supported.