Google Plus - stylized as Google+, is all the Buzz right now (pun intended). However, the service is invite only for now, so you'd have to snoop around your social Circles to score an invite. But what if you already have an invite for the desktop and want to use it on your phone? Well then you have two options - an HTML5 based mobile version for Android and iOS devices and a native Android app with additional features.
Unfortunately though, the Android app isn't available worldwide right now so you'd have to aquire it via other means. Here's what you can do to get your hands on the official Google+ app if its not available in your market.
For Root Users
If you are already rooted, then all you have to do is use MarketEnabler to fake your phone's provider as T-Mobile USA or Verizon Wireless. Once that's done, fire up the Android Market and search for Google+ or pub:Google and you'd find the Google+ app in the search results.
Installing it from that point onwards is straight forward but you wont be able to access it unless you already have an invite and setup your account on a PC.
Updated:The Google Plus app now handles multiple Google login IDs at initial start-up.
If you don't have a rooted device or don't want to use MarketEnabler for some reason, then just download the Google+ APK from here (direct download link). You must have unknown sources enabled in the Applications settings of your device to side load packages.
Once installed, you can access Google+ if you already have an invite. If not, then just drop us a comment below with your gmail id and we will be happy to send you an invite.