Interested in learning how to make apps for Windows Phone 8.1? Or are you just interested in software development in general? Either way, here's a great—and free—way to get it done, using two free new instructional video series from Microsoft and the software giant's amazing free development tools.

Learn how

There are two video series available from Microsoft that can help you learn to write Windows Phone 8.1 apps.

If you're just starting out, please be sure to check out Bob Tabor's Windows Phone 8.1 Development for Absolute Beginners. This 30-episode series clocks in at 9 hours total, and includes the following topics:

Windows Phone UI with XAML layout and events
Navigation model
Application lifecycle
Working with the Windows Phone Emulator
Understanding MVVM (Model-View-ViewModel)
HTML apps in the WebView
Storage
Maps
Animations
Media (Video/Audio with the MediaElement control)

More experienced? As they did before for each subsequent version of Windows Phone, Microsoft has also issued a series of videos that will teach you everything you need to know to develop apps for Windows Phone 8.1. Called Building Apps for Windows Phone 8.1 Jump Start, this amazing video series stars Andy Wigley and Matthias Shapiro and consists of a whopping 23 videos:

Introducing the Windows Phone 8.1 App Development Platform
Getting Started Building Windows Runtime Apps
Page Navigation and Data Binding in Windows Runtime Apps
Lists and Lists Items in Windows Runtime Apps
Programming Page Controls and Page Transitions Animations
Adapting UI for Different Screens and Orientations
Windows Runtime App Lifecycle
Localization and Globalization in Windows Runtime Apps
Data Storage, Backup, and Roaming
Sharing Files and Data in Windows Phone 8.1
Background Tasks and Multitasking
Maps, Geolocation, and Geofencing
Networking, Mobile Services, and Authentication
Tiles, Notifications, and Action Center
Sensors and Proximity: NFC and Bluetooth
Interacting with User Data: Contacts and Appointments
Camera, Media, and Audio in Windows Phone 8.1
Windows Phone 8.1 for the Enterprise Developer
Programming SQLite on Windows Phone 8.1
Tooling and Diagnostics
App Packaging, Monetization, and Publication
Universal Apps for Windows
Silverlight apps on Windows Phone 8.1

Get the free tools

As you may know, Microsoft makes various versions of its Visual Studio integrated development environment (IDE) available for free, including versions for web, Windows desktop, Windows (Modern) development. Previous, to Windows Phone 8.1, it also made a free version of Visual Studio available for Windows Phone as well. But with Windows Phone 8.1, you now need the Windows version, which now goes by the awkward name Microsoft Visual Studio Express 2013 with Update 2 for Windows. You can find this solution on the Microsoft web site and use to create Windows apps, Windows Phone apps, or new universal apps for both Windows and Windows Phone.

Have fun!