Fibonacci in C#

Ok, I couldn't wait for the weekend. Here's my first try:

namespace Fibonacci
{
    class Program
    {
        public static IEnumerable fib(int number)
        {
            int counter = 0;
            int a = 0, b = 1;
            
            while (counter++ < number)
            {
                yield return b;
                
                int previousA = a;
                
                a = b;
                b = previousA + b;
            }
        }
        
        static void Main(string[] args)
        {
            // Display fib
            foreach (int i in fib(10))
            {
                Console.WriteLine("{0} ", i);
            }
        }
    }
}