OLYMPIA, Wash. -- Taxes can be confusing, especially if you’re a business owner. But the Department of Revenue has developed an iPhone app that uses GPS to determine the local tax rate for any location. Mike Gowrylow with the department says this is a quick and easy way for business owners to check the tax rate, location and confirmation code for whatever area they’re servicing. Gowrylow says this app is particularly useful for mobile businesses such as contractors, but also for retailers who regularly ship products. He says an Android app is in the works. You can download this app at www.dor.wa.gov/taxratemobile.