For development Visual Studio 2010 installed on a machine with SharePoint 2010 is required. To set up a SharePoint 2010 development environment follow the guide on MSDN: Setting Up the Development Environment for SharePoint 2010 on Windows Vista, Windows 7, and Windows Server 2008
To create a soluction package (.wsp file) from Visual Studio right click the project and "Package"
The wsp file will be created in the bin\debug or bin\release folder depending on the current build configuration