From http://iosdevelopertips.com/cocoa/date-formatters-examples-take-3.html

NSDate to NSString

NSString *dateStr = @"20081122";
 
// Convert string to date object
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"yyyyMMdd"];
NSDate *date = [dateFormat dateFromString:dateStr];  
 
// Convert date object to desired output format
[dateFormat setDateFormat:@"EEEE MMMM d, YYYY"];
dateStr = [dateFormat stringFromDate:date];  
[dateFormat release];