How can I get the first element in an NSDictionary?

I have an array of NSDictionaries. How can I pull out the first element in the dictionary?

   NSArray *messages = [[results objectForKey:@"messages"] valueForKey:@"message"];         
    for (NSDictionary *message in messages)
    {
        STObject *mySTObject = [[STObject alloc] init];
        mySTObject.stID = [message valueForKey:@"id"];      
        stID = mySTObject.stID;
    }

[Updated to use firstObject, as described in another answer, which has the benefit of returning nil for an empty array.]

There is no "first" element in an NSDictionary; its members have no guaranteed order. If you just want one object from a dictionary, but don't care which key it's associated with, you can do:

id val = yourDict.allValues.firstObject;

(There's also lastObject, which has been around since 10.0(!).)

(Old, pre 10.6 version:)

id val = nil;
NSArray *values = [yourDict allValues];
    
if ([values count] != 0)
    val = [values objectAtIndex:0];