Yes, it's a third-party application, but at least a Google Voice application of some sort has arrived in the Palm App Catalog. Along with nine other new applications, gDial Pro offers Palm Pre (and soon to be Palm Pixi) users the ability to access Google Voice's various features, including a dialer, recent calls screen, text messages screen, and what looks to be a favorites menu.
Personally, my favorite feature on the Google Voice applications that I've used is the ability to dial out using my Google Voice number. Since I give it out as my office line, it's nice to call PR people from my actual GV number (that's likely to be in their address book), instead of a number that they don't have. Keep it up, Palm - your App Catalog is starting to shine.
Source: Engadget Mobile