Great news! As of December 2014, the US government and President Obama have decided to ease sanctions imposed against Cuba under the old US embargo that was created in the 1960's.
The embargo hasn't been ended entirely, but these are some significant changes. When it comes to USA to Cuba travel, here is what it means for you:
In addition, we also recommend bringing cash so that you can convert it to Cuban pesos after arriving here. You never know when you'll need cash, and there may be some places you'll visit that do not take credit cards!