Cannot create new Web Application in Sharepoint 2007

I'm a Sharepoint 开发者_开发技巧Beginner and i have a question : I setup a Develop machine with there step : IIS, VS 2008, MOSS 2007. At first, it works, but i have realized that, i cannot create a new web application : From Sharepoint Site Administrator/Application Manager/ Create or extend ... It says that the Web application created successful. But in fact, there's no new Web application created ( I checked it in IIS ) Please Help me

Are you getting confused between site collections (IIS Web site) - and sites and webs, which are containers inside a site collection which exists in SQL Server and is mapped to the URL of the site collection .. ??