The Wall Street Journal has just reported that Google plans to launch its very own phone service starting tomorrow. The plan was first announced over a month ago at Mobile World Congress in Barcelona, but the WSJ has since unearthed more details about it. The service will initially only be available on Nexus 6 handsets and will piggyback on Sprint and T-Mobile networks -- it'll switch between the two depending on which has the strongest signal. Most intriguing, however, is the revelation that the wireless service will let customers pay only for the data they consume per month. What's more, it'll also let you route calls and data through WiFi, which could reduce bills even further. There's not much else we know about Google's first stab at running its own phone service, but if its goal is to shake up the wireless industry, it looks like it certainly will.