The Simply Everything plans include unlimited data while on the Sprint network. Effective July 11, 2010, we updated our terms and conditions for phone plans to include a new 300 MB per month data roaming limitation. There are no overage charges for exceeding the limitation but if it occurs for 3 months we will send you a warning letter. Hope this and the previous post answered all your questions.
If you have a plan that includes roaming /data then yes while in the US, if you are on the data while roaming that is covered. The data roaming is not covered if you are outside the US. The phone prompts that to let you know if you do not have the right plan you may get charged. You can go through the settings of the device to turn off the roam data guard.
Yesterday I got maybe 6 warnings on my Samsung Epic 4G saying Data Roaming Charges May Apply. I have the Sprint "Unlimited" data/text plan. My question is does this plan cover the Data Roaming areas. I saw a thread on this topic from 2009 that said yes it is covered no extra charges but that was 2 years old. Does anyone know where I can get an official answer to this?