Download the Latest Android Market Update and Install it Manually
Waiting on that awesome +1 button in your Android market? Need to lock access to your market down to keep people from buying/installing or uninstalling apps? If you havenít gotten the latest update yet, you can manually install it by downloading the APK file (here) and installing it like you would any third party app. Be sure to have Unknown/Third-Party Sources enabled in Settings > Applications. Weíre aware that some of you havenít even gotten the first update (the one that first introduced the UI changes). No use in waiting, really Ė these are all the same APK files that users would otherwise get over-the-air. Your phone wonít explode into nothingness if you install it. And you donít need to be rooted. Get to it!
SOURCE: Download: Phone Android Market 3.1.3 Adds +1 For Apps And Games, PIN Number For Purchases, And More