While Google released its Google+ social network without territorial limitations, the mobile app was only released in limited number of countries. For instance, even majority of countries inside the European Union don't have the Google+ app activated and accessible through Google Marketplace.
However, enthusiasts around the world quickly found the way around, and if you want to download Google+ Mobile app and see the Instant Upload and Huddle features, you can do it thanks to cloud storage, courtesy of Dropbox
We have received the following Dropbox link and installed Google+ on this authors' HTC Desire HD - works like a charm. In case the Dropbox link goes dead, we've also uploaded it to MegaUpload service.
Google+ Android App Download on Dropbox
Google+ Android App Download on Megaupload
NOTE: You do not need to have a rooted device to install the app on your phone.
You can see the application overview here: