To find actual Server updates, keep track of this thread: http://forum.ea.com/eaforum/posts/list/9337881.page#27456857
SimCity Patch notes are found here: https://help.ea.com/article/simcity-patch-notes
Regular Blog updates are posted on the US SimCity site, found here: http://www.simcity.com/en_US/blog
If it redirects you to your language, type en_US after www.simcity.com/ to go to the US site.
New Test server! http://forum.ea.com/eaforum/posts/list/9354378.page
And the best place is the twitter page: www.twitter.com/simcity/