[GadgetKen]

ETECSA (Empresa de Telecomunicaciones de Cuba S.A) used to have offices in Jose Marti airport in Havana(terminal 2 or 3). You could get a local prepaid sim card with the following rates: http://www.etecsa.cu/index.php?page=...cubacel_tarifa

Rates are in convertible pesos (CUC) that are pegged to the US dollar. There will likely be a 10% fee to convert USD to CUC. Credit cards with US banks probably will not work in Cuba due to embargo restrictions.

Local rates are .35 CUC peak (7 AM-11 PM) or .10 CUC off-peak (11 PM-7 AM). Rates to North America are excessive at 1.60 CUC. In theory a callback card could be used in conjunction with the local number but the combined rates would be the same or higher for many callback cards.

Other options I can think of would be (and all are expensive):
1. International callback sim card.
2. VOIP but internet is costly and latency pretty bad due to satellite back-haul mentioned in other posts.
3. Low tech local calling card but international calls to US have rates that aren't much better than a local sim card.
4. A prepaid sim card from a country other than the US that has Cuba roaming capabilities (e.g. Digicel), but rates will also be pricey.
5. Use a satphone that doesn't block calls from Cuba due to US embargo restrictions. Would likely be cheaper than other alternatives on a per minute basis.