We went there a couple of years ago – cycling is a great way to see the country. We flew with Virgin who at the time allowed bikes to go for free and left our bike boxes at the casa in Havana.
Stay in casa particulares rather than the state owned hotels as the food in hotels is abysmal. The casas can be really romantic places to stay, the owners are usually lovely people and the food is fantastic – lobster for $10?
Some basic spanish will help and go between Nov – April to avoid monsoon season
Buses and taxis are very happy to take bikes so that you can see more of the country
A really good book is Bicycling in Cuba – can’t remember author sorry, Lonely Planet also do a guide to cycling but we found this one to be inaccurate and unimaginitive in the itineraies it suggested
If you post your e-mail address I can give you more info if you want