The exchange rate is roughly 19,040 dong to $1.00 (8.09.10). This is close enough for most street transactions.
You will probably want to change about $50 - $100 into dong. You will have ample time to do so. Keep in mind that over the last couple years, banks have dramatically increased the fees they charge for overseas transactions using credit and debit cards. While these fees are legal, they're basically another way for credit card companies to wring a few more dollars out of their customers.
For years, Visa and MasterCard have levied a 1 percent fee on international transactions. Recently, banks that issue those cards are tacking on an additional 1 percent to 2 percent. These are often called "currency-conversion fees" or "foreign transaction fees." (You'll also be charged a fee for withdrawing cash using your ATM card, so there's no way to get by completely fee-free.)
You should check with your Credit Card Issuer and see which one has the lowest fees.
You will be charged a fee of 3-5% for exchanging traveler’s checks.
