Banks:  There is a Banamex in San Blas with an ATM that works most of the time.  There are times when it runs out of money or is down for other reasons so don't wait until you're down to  your last 10 pesos before taking out money.  It is best to use the ATM when the bank is open, in case it eats your card which is a more common occurrence down here.   There is a new ATM by the gas station but I don't use it since a few people have lost their cards there.

Sending Money:  There always seems to be a lot of problems associated with sending money to San Blas and the fees are very high.  I think it's best to bring a valid ATM card and have the person send the money to your bank in your home country.

Papers:  You need a tourist visa to visit San Blas.  You can get it at the border or at the airport.  It costs around 20 USD and if you ask, you can get it for up to 6 months.  They will not ask you for it when you enter Mexico because for most the areas around the border you do not need the tourist card.  You must ask them where to get it and how to pay for it. If you forget, or your visa expires, you can go to Tepic or Puerta Vallarta to get one, but this is a huge hassle. If you want to live down here you will need to apply for FM3 papers and show proof of an income.

Passports: Starting in January, 2007, Americans will be required to carry US passports if they are returning by air. Starting June 2007 they say you will need passport to cross by land.

Cars:  You can bring  car with you on a tourist card, but you will have to register it, and leave a 500USD deposit, either in cash or with your credit card.  If you do not return the car on time you will forfit the $500 and not be allowed to bring another car into Mexico.  You should get Mexican car insurance.

Dogs:  You can bring you dog to Mexico.  Always carry proof of vacinations.