We're sorry. Google Music is currently only available in the United States

Solution:
Set your Proxy IP Address to 75.109.154.41 and port 3128 so that you can visit to this site with no limits.

Getting started:

First, open Mozilla Firefox Browser

Second, got to Tools tab at the upper part of the application and click Options

Third, click the Advance selection at the upper right part and click the Network tab beside General tab

Fourth, click Settings then choose Manual proxy configuration

Fifth, write 75.109.154.41 or copy this number with dot to the HTTP Proxy

Sixth, write 3128 or copy this number to the Port beside HTTP Proxy

Seventh, click the box under the HTTP Proxy "Use this proxy server for all protocols"

Eight, click OK and another OK.

Ninth, go to the url box on Mozilla Browser

Tenth, enter this url music.google. 

Screenshot: