If you are looking for cross-platform development within Visual Studio, Xamarin is a great option to build applications not just for Windows, also for iOS and Android devices in C#, the language we all love.
Along with the Office 365 API Tools for Visual Studio 2013, you also get a rich set of Office 365 API .NET and Cordova client libraries to interact with the Office 365 APIs.
UPDATE: Office 365 API Tool is now included with Office Developer Tools and brings breaking changes to the Office 365 API Authentication Library.
Office Developer Tools uses the Web Platform Installer (WebPI) to install the latest version of the tools.
Today we released Office Developer Tools for VS2012 RTW and is available for download here – http://aka.ms/OfficeDevToolsForVS2012 There are some great updates to this release, few mentioned below: First and foremost, you do not need to run Visual Studio 2012 as an administrator to build apps for SharePoint!
Today, we made available Visual Studio 2012 RTM for MSDN subscribers However Visual Studio 2012 RTM does not include the Office 2013 and SharePoint 2013 Developer Tools Preview with it.
Microsoft released Visual Studio 11 Beta last week – This also includes Team Foundation Server (TFS) 11.