The Welcome page defines the page that is loaded when a user navigates to a site.
To change the Welcome page of a site, do the following:
On the Site Actions menu , point to Site Settings, and then click Modify All Site Settings.
Note: If no menu appears when you point to Site Settings, click Site Settings to open the Site Settings page.
On the Site Settings page, under Look and Feel, click Welcome page.
In the Welcome Page section, click Browse to find the Welcome Page that you want to use for the site, and then double-click the item to select it.