Palm Introduced its new Treo Pro smartphone on Wednesday with features aimed at stemming losses to the iPhone 3G camp. The latest Treo sports 3G support, a built-in GPS, Wi-Fi and Bluetooth, and will be available as an unlocked handset in the U.S., allowing it to be used with any GSM-based cell carrier.

Palm’s new Treo Pro

The Treo Pro will include a ringer silencer switch (like the Treo 650 -- and now the iPhone -- do), dedicated email and calendar buttons, a touch screen, mini-QWERTY keyboard, a standard stereo headphone jack, and will run on Microsoft’s Windows Mobile 6.1 operating system. The Treo Pro’s battery is user-replacable, which potentially gives the device a leg up on the iPhone 3G with road warriors that regularly drain their batteries throughout the day.

Like other Palm devices, the Treo Pro relies on a stylus for touch screen interfacing, and forgoes Apple’s software-based keyboard for a physical one. Palm is also touting that the Treo Pro supports tethering, or using the phone as a modem for your laptop, right out of the box.

Compared to the base iPhone’s 8GB of memory, the Treo Pro’s 256MB seems paltry, but the device does include a microSDHC card slot for memory expansion.

At US$549, the Treo Pro costs substantially more the the 16GB iPhone 3G at $299. It won’t be available in the U.S. until fall, so users waiting to see how the Treo Pro stacks up against the iPhone 3G under real world conditions will have to wait a couple of months.