ASP .NET 3.5 Namespaces

Commonly Used Types and Namespaces

System.Web
HttpApplication
HttpCookie
HttpRequest
HttpResponse
HttpRuntime
HttpServerUtility

System.Web.ApplicationServices NEW
AuthenticationService NEW
ProfileService NEW
RoleService NEW

System.Web.Caching
Cache

System.Web.ClientServices NEW
ClientFormsIdentity NEW
ClientRolePrincipal NEW
ConnectivityStatus NEW

System.Web.ClientServices.Providers NEW
ClientFormsAuthenticationMembershipProvider NEW
ClientRoleProvider NEW

System.Web.Compilation
BuildProvider

System.Web.Configuration
WebConfigurationManager NEW

System.Web.Hosting
ApplicationManager

System.Web.Management
WebBasedEvent

System.Web.Security
FormsAuthentication
FormsIdentity
Membership
Roles

System.Web.SessionState
HttpSessionState

System.Web.UI
Control
MasterPage
Page
ScriptManager NEW
System.Web.UI
UpdatePanel NEW
UpdateProgress NEW
UserControl

System.Web.UI.HtmlControls
HtmlButton
HtmlControl
HtmlForm
HtmlInputControl

System.Web.UI.WebControls
Content
DetailsView
FormView
GridView
LinqDataSource
ListView
LogIn
Menu
ObjectDataSources
TreeView
Wizard

System.Web.UI.WebControls.WebParts
WebPart

*New - New namespaces in .NET framework 3.5

Source:http://msdn.microsoft.com/netframework