The Algerian currency is the Dinar DZD As of Dec 2010, 1 US $ will give you 73 Dinar. There are Coins in the order of 5 DA, DA 10, 20DA, 50DA, and 100DA and notes in the size of 100DA, 200DA, 500DA, 1000DA, 2000DA.
Money can be exchanged at Banks or Post offices. Make sure that the exchanged bills are in a good condition, people tend to be picky with accepting ripped and older bills. Be careful with other currencies than Euro or US$ it could be hard to find a bank that exchange less common currencies.
ATMs are widely available and can be found in every post office or larger bank you can withdraw Algerian Dinar with any major credit card and maestro cards. If a pin with 6 numbers is necessary just enter two zeros before your pin.
Living in Algeria is very cheap compared to western conditions for an example 300 DA will get you a full meal or bus ride from Algiers to Oran 400km. Renting a midsized apartment will cost normally 60.000 6 month in the advance DA a month.