adAway is a freeware tool which handles the task of blocking advertisements from showing up on your Android device. The application comes with a straightforward interface and you can easily customize which ads serving hosts are blocked and which are allowed. There's also a button for disabling ad blocking altogether. You can see the list of your hosts sources and after you make changes regarding this subject, the app requires a device reboot.
Some users might consider the next issue as being a drawback. adAway only provides the full set of features if the device is rooted. You can configure the application to check for updates at start, hide the reboot dialog, IP redirection for blocked hosts and more. There's also a webserver listening available and you can configure it to answer requests.
Another nice feature is the ability to create exceptions and receive ads coming from those specific locations. You can also download hosts files inside the interface and you're not forced to create yours all the time.