simulating cache

Question

Hi ! I have to implement a Web Service that receives and sends queries from an ASP.NET App to a Native XML Database. I have to store those results in some kind of "cache", so that if the same query is received from the ASP.NET App again, the WebService sends back the cached result, and doesnt run the query again against the database. any ideas about how could I 'simulate' the 'cache' ? Any help would be appreciated. Thx guys !