If you're talking about the Page "Title", that is nothing more than setting the Title property of the page. Good place to do this is in the Page_Load() event handler.

Code:
    protected void Page_Load(object sender, EventArgs e)
    {
      	this.Title = "New Title";
    }
I just quickly created a test project using one of Microsoft's ASP templates which uses master pages (the Personal Design website). One thing I noticed, is that not every one of the pages had a "code behind page". For one that did, I was able to access this event handler.

For a page that did NOT already have a code behind page, I've never tried to create a code behind page...
but here's a link to how to do that:
http://weblogs.asp.net/jgalloway/arc...in-vs2005.aspx