Finding

System.Collections.ArrayList myArrayList = new System.Collections.ArrayList(); 
myArrayList.Add("GBP"); 
myArrayList.Add("USD"); 
myArrayList.Add("EUR"); 
Console.WriteLine(myArrayList[1]); 

Contains

Does an Element Exist

if (myArrayList.Contains(sElement) == true) 
{ 
} 

IndexOf

Returns the index of the element in the collection, or -1 if it cannot be found.

LastIndexOf