Do you choo-choo-choose the Sprint Express, or does it choose you? The Now Network's mixing things up this holiday season by adding its own branded device -- in reality, a reworked Huawei Boulder that Sprint slapped its name on -- to the low end of its smartphone lineup. Known simply as the Express, it's a portrait QWERTY Android 2.3 handset that will set you back $20 with a two-year contract (after a