I always use peso. You can change money at the airport, use an ATM there, or after you get to town there are "casa de cambio" (change windows) nearly everywhere with their rates posted.

Most larger hotels, shops, and restaurants accept charge cards (but not all smaller, local places do). If you decide to take TC's you will likely need cash them at your hotel front desk or a bank, rather than spending directly in shops or restaurants. While many places may accept US dollar, you'll get a better rate if you convert yourself or withdraw direct from an ATM.

Thanks Suze. I appreciate your help. I'm rather new at this so I may post some more questions as they come up. It's obviuos from other posts that you know the area well and that you're a big fan so any input would be greatly appreciated. I promise not to attack

keep a sharp eye on your credit card in mexico. it is best to pay CASH in pesos for most transactions. use the credit card for your car rental and for paying for your tours IF it with a reputable agent in your hotel lobby, but dont hand it over easily or often. a common scam is for the card to be swiped twice and once youre home, its a difficulty you really really wont want to deal with.
from what i recall the pv airport had great rates posted. get a few hundred dollars worth of pesos as soon as you arrive right there at the airport. are you being picked up or do you plan to take a taxi to your hotel? if you take a taxi always find out the rate to your destination with hotel front desk and ask taxidriver upfront what he's charging. compare. expect to pay same rate back. at airport there is a taxi ticket you can buy for use to your hotel.
also watch out for sneaky timeshare tactics. they offer free this or that for a few hours of your time. sometimes they pretend to be something other than they are ie., they'll say they are your taxi driver or waiter. if they approach you and you catch a whiff of what theyre up to, tell them to buzz off.
keep your stuff safe at front desk, or if your rm has a safe, in there.
have a lovely trip darling. pv is a great holiday choice!

Ditto to Seldomred> We had a credit card pickpocketed last May on a street one block from the ocean and within 50 minutes they had gone to Wal-Mart and used the card. Wal-Mart evidently does not ask for ID or authorization. We let our guard down because PV has just been so safe. It was our own fault for not thinking. You have to be careful everywhere you are, home or abroad. Our bank said credit card fraud for tourists in Mexico is rampant. Even though it is convenient, try to use pesos, or USD, especially in restaurants. I do not recommend TC. The Mexican shops prefer USD but its to your advantage to convert to pesos. P.S. Before taking your credit card to Mexico, call your bank and be sure and get a correct number to call from Mexico to cancel the card in case it gets stolen. The number on the back is probably not good, it wasn't for us. PV is safe, but its getting bigger and criminals naturally gravitate to the crowds. Just don't let anybody try to "help" wipe off mustard or some substance that just happens to hit you. They work in pairs, one wipes and one gets your wallet.

As always, low/no fee ATMs for cash and CC's for Hot/Rest where you'll not get discounts.
All else is nonsense.
M (TA local expert for SMdA,MX)