What are some restricted items that I can't take to Cuba with me?

Question

I have heard that I won't be able to take my cell phone. Someone told me that items like that can be used to overthrow the government, and therefore prohibited. I am thinking of travelling there in a week when I finish my finals this semester. If you know anything about this, please let me know. I'd hate to be caught trying to bring something in (accidentally) that I'm not supposed to have. Thanks in advance!