Please note that AdFree Android has now been removed by Google from the Google Play Store.
AdFree Android is an Android utility that modifies your phone's host file to block ads.
Ads can be a pesky thing and can even drain your battery life by running processor intensive animations. Android users can remedy this by downloading AdFree Android. The app works extremely well is and very easy to setup.
Simply install the application, downloaded an updated host file and reboot your phone to flush the DNS. You'll immediately notice that apps that displayed ads won't do so any longer. This works across the operating system. This approach to ad blocking is great as AdFree Android doesn't have to run in the background constantly.
The biggest downside of AdFree Android is that it requires root permissions to run. For those without root, try Adblock Plus instead, though that will limit you to blocking ads only while on Wi-Fi. AdFree Android will only ask for root permission once. You can even set it up to update the host file automatically so you'll have to run the app yourself.
Overall, AdFree Android is the best ad blocking solution on Android. The only catch is that you need a rooted phone.