While the amount of data smartphone owners used each month wasn’t relevant until last June of 2010 when AT&T announced a 2GB data cap, it is now.

If you’re an iPhone user that often streams video, audio and download files from the internet, you probably keep a close eye on your data usage. If you’re a new iPhone owner and have no idea of how to check the amount of data you’ve used for your current billing cycle, its fairly simply. There are several ways to check your data usage.

You can either check your data usage online from your AT&T/Verizon account, or if you have AT&T, you can download the AT&T My Account app from the App Store for free. Additionally, you may also check data usage right from your iDevice, by navigating to: Settings > General> Usage.

As you can see I haven’t used much data since I’m using an unlocked iPhone on T-Mobile, which only allows for an EDGE connection.

We’re curious to see how much data you use per month? Let us know in the comments!