Yes, The Interview is now available online (Google Play and You Tube for sure and possibly other sites) to rent or buy. However, at the moment this is only available to people in the USA.
Independent cinemas will also be showing the film, though personally I would be a little dubious about viewing it in this way as I would be worried about repercussions (hackers thought to be affiliated with the North Korean government have threatened to attack cinemas that show the film). That said, if we think this way and give in, then the haters will get what they want.
Although the film can technically only be viewed by people in the US, there are ways of course, of tricking your server into believing that you live there. All you need is a VPN (Virtual Private Network) which acts as a shield and disguises your actual location.
There are many VPN service providers, but one that is free (although there is a paid version) and genuine is CyberGhost who are offering a 50% discount on their premium services before 10th January 2015.