Well, now I read your question, and it isn't about a Servlet in particular, but a Tomcat question. So I will move this thread to the Apache/Tomcat forum.
The regular installation of Tomcat includes documentation files that cover all questions like this. If you can see the regular Tomcat startup screen, you are in business. Bill
You don't drop it anywhere and hope it works. You'll have to package it someway and deploy it in tomcat, by deploying, the least thing to do is to let tomcat know you've come up with some servlets and the path to get to it. As one option, Tomcat has a manager that lets you deploy your application which I found very useful during development.
Hi I suggest you put it in Tomcat5/webapps/YourApp/WEB-INF ..., The book Head First Servlet & JSP is a pretty good one for whoever wants to learn servlet and JSP, It has the whole chapter on deploying webapps, I suggest you to buy it