SharePoint 2010: Three ways to change Home Page

From Browser 

• Open SharePoint Site
• Navigate to page you are going set as Home page.
• Click to the home page
• Click Make Home page from ribbon under Page Actions Group.

Property bag Feature

• Open visual Studio 2010.
• Create new empty SharePoint Project “SetHomePage”.
• Add new empty element “HomePagePropertyBag”
• Copy the relative page URL that you want to set as home page.
• Write the following lines your Properbag features. 

<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
<PropertyBag Url="" ParentType="Folder" RootWebOnly="false">
<Property Name="vti_welcomePage" Type="string"
Value="lib/TestWelcomePage.aspx"></Property>
</PropertyBag>
</Elements>

SharePoint Object model

• Open visual Studio 2010.
• Create New Empty SharePoint Project “SetHomePageByCode”
• Add new feature
• Add new feature recover.
• On feature activation write the following lines of code. 

public override void FeatureActivated(SPFeatureReceiverProperties properties)
{
SPWeb _Web=null;
if (properties.Feature.Parent is SPWeb)
{
_Web = (SPWeb)properties.Feature.Parent;
}
else if (properties.Feature.Parent is SPSite)
{
_Web = ((SPSite)properties.Feature.Parent).RootWeb;
}
if (_Web != null)
{
SPFolder _rootFolder = _Web.RootFolder;
_rootFolder.WelcomePage = "lib/TestWelcomePage.aspx";
_rootFolder.Update();
}
}