Windows Phone Pro

The Windows Phone interface has two primary components – the System Tray and the Application Bar.
Application Bar – Area at the bottom of the interface which provides a access to the most common tasks.  For tasks which are less common, applications can add a single menu which is launched from the application bar. he [...]

The following Silverlight controls are available for Windows Phone development:

Border
Button
Canvas
CheckBox
ContentControl
ContentPresenter
Control
Grid
HyperlinkButton
Image
InkPresenter
ListBox
MediaElement
MultiScaleImage
Panel
PasswordBox
ProgressBar
RadioButton
ScrollViewer
Slider
StackPanel
TextBlock
TextBox
UserControl

One important issue to note is that the ListBox control will in future be replaced by the ListView control in future updates to the development environment.

The back button is a key feature differentiating Windows Phone from the iPhone and Android.The hardware back button is mandatory on all Windows Phones and will likely be a key navigation feature in Windows Phone applications.
The back button is used to navigate back within an application. Normally developers do not have to worry about [...]

Windows phone apps are based on the Silverlight page model where users can navigate forward through content screens . Using the hardware back button, users can easily navigate backwards.
The core elements of the page UI are a top-level container control named PhoneApplicationFrame which can host a PhoneApplicationPage. These are analogous to the standard  Frame [...]

Silverlight will be the primary development technology for Windows Phone. Initially, only a subset of Silverlight 3 features plus the new features of Silverlight 4 will be will available. The supported features of Silverlight 3 will be:

Input
UI rendering
Media
Deep Zoom
Controls
Layout
Data binding
Isolated storage
Networking (HttpWebRequest, WebClient)
XAML
XAP packaging
XML serialization
Windows Communication Foundation (WCF)

In addition, there are several new Silverlight features [...]

The Windows Phone Marketplace was demoed for the first time at Mix 2010. The Marketplace is of great interest to developers as Apple’s App Store has proved a great distribution model for small application developers. However the App Store has shown signs of a growing pains of late and the Windows Phone Marketplace looks to [...]

At Mix 2010 Microsoft unveiled the first CTP’s of the tools developers can use to build Windows Phone apps. The Windows Phone Developer toolkit can be downloaded here .
The developer tools CTP is a single install which contains the below tools:

Visual Studio 2010 Express for Windows Phone CTP
Windows Phone Emulator CTP
Silverlight for Windows Phone CTP
XNA [...]

In leaked documents, Microsoft has outline the development platform for the Windows Phone OS and the key development environment for Win Phone games will be XNA.
XNA is the development environment for both XBox LIVE and the ZuneHD. This appears to confirm that the XBox LIVE games will be ported to the Win Phone platform  and [...]

Althought not meant to be officially released until Mix 2010, details of the Windows Phone Application Platform have already been leaked.
Application Platform Components
The core components of the application platform will be Visual Studio 2010 and Expression Blend. The Windows phone emulator is a Visual Studio addin which will enable VS to emulate the Win Phone [...]

At MWC Microsoft demoed Windows Phone 7  but developer details were sparse – one key question is what will be the database service. SQL Server CE was the provider for Windows Mobile 6x but Microsoft promised to make an announcement on the Win Phone 7 SQL Server details at Mix in March 2010.