>Im working on a Visual Basic.Net 2003 project, and I want to program a button by clickin him and then open a web site on the Internet Explorer.
>Wich function should I use to do it??
>I don´t know anything about it, please help me!!

You can try something like:

System.Diagnostics.Process.Start(ComboBox1.Text)

You may replace the ComboBox1.Text with your value.