Small businesses that are wrestling with the double whammy of higher input costs and softening demand seem to be finally letting go of their dread for mastering new riffs on mobile software. Steve Jobs has been repeatedly quoted saying AppleAAPL generated $30 million in sales the first month for the so-called App Store that sells downloadable software for the uber-chic iPhone. And cell-phone operators from VerizonVZ to T-Mobile to Sprint NextelS are answering by pushing business applications for mobile platforms with fresh vigor. I am finding, though, that the most interesting end of the mobile app market is the product lineup from smaller start-ups, which are creating easy-to-use mobile apps that are perfect for small businesses. Most of these are simple to install and sometimes free and can be used to quickly boost productivity and save a couple gallons of pricey diesel fuel.