Avoid shipping money or goods through Federal Express. As of April of 2010, Cuba is on FedEx's list of countries that the company refuses to ship to. Also on this list are Syria, Iran and North Korea.
Cross the border to ship your package or mail your check. You may be able to send mail to Cuba from either Canada or Mexico, using their postal systems or a Canadian or Mexican shipping company. If you live along the U.S. border with either of these countries, this may be an easier option for you.
Send money electronically to your contact in Cuba. Two services capable of this are PayPal and Western Union. There may be some charges associated with this transfer.
Speak with your local U.S. Post Office clerk. Currently, the USPS allows postal customers to send mail to Cuba in the form of standard letters sent via First-Class Mail International, International Priority Airmail (IPA) or International Surface Air Lift (ISAL) mailings. However, prior to mailing your check, money order or other form of currency, you will need to contact the Office of Foreign Assets Control (OFAC) in the U.S. Department of the Treasury for current regulations and to be apprised of all relevant regulations pertaining to items mailed from the U.S. to Cuba.