GoSolarUSA (http://www.GoSolarUSA.com) has announced a deal today with Chinese developer Yosion to bring that company’s Apple Peel 520 product to the U.S. The device purportedly lets the iPod touch operate as a smartphone.

Both companies signed a funding option agreement last week. Under the agreement, GoSolarUSA will work with Yosion to develop the Apple Peel 520, file for a U.S. patent and distribute it in the U.S.

When used with Apple’s (NASDAQ:AAPL) iPod Touch, the Apple Peel 520 functions as a protective skin that adds mobile voice and text messaging capabilities to the touch-screen media player. Yosion announced last week that September’s initial manufacturing run is already sold out.

The Apple Peel 520 is the creation of 22-year-old Chinese programmer Pan Yong. The gadget slips over the iPod touch’s case and includes a battery, dock connector and SIM card. Once the proper software is installed, the Apple Peel adds the ability to make voice calls and text messages using the touch.

When fully charged, the Apple Peel’s 800mAh battery offers nearly five hours of talk time and 120 hours of standby use. Pricing hasn’t been announced.