Changing Money, Traveler's Checks
You can buy a cheap cell phone in Guatemala for as little as 125 quetzales, which about $17 in October, 2008. It is not necessary to open an account with the phone company.
Credit cards are accepted in many Panajachel businesses, but cash is king around the rest of the lake. In San Pedro, Casa Verde, Alegre Pub and Mini-Mart Johanna take credit Visa, MC and AMEX.
Using an ATM, or Cajero Automatico
In Pana, there is an ATM next to Phatburger at the north end of Santander, and another beside Comercio Rafael. San Pedro's ATM's are at the bank in el centro and just up from the Pana dock across the street from Chile's Restaurant. All ATM's are often empty when lots of tourists hit town, so don't wait until the last minute.
Travelers Checks
The bank in el centro and Hotel Lago Mansion up from the Panajachel docks will cash most travelers checks. So will Panajachel banks. Few hotels and hostels in San Pedro and other towns around the lake accept traveler's checks, though the big ones in Panajachel have been known to do so.
The Banrural bank in San Pedro limits U.S. dollar exchanges to $1,000 per month.
If you need money wired to you, the bank receives (and sends) Moneygram and Western Union transfers.