Try This,
NSMutableArray *timeZoneArray = [[NSMutableArray alloc] initWithArray:[NSTimeZone knownTimeZoneNames]];
NSMutableArray *abbreviationArray = [[NSMutableArray alloc] init];
for (int count=0; count < [timeZoneArray count]-1; count=count+1)
{
[abbreviationArray addObject:[[NSTimeZone timeZoneWithName:[timeZoneArray objectAtIndex:count]] abbreviation]];
}
NSLog(@"Abbreviation : %@",abbreviationArray);