Windows CE: Standard Software Development Kit (SDK) V 1.0

http://www.microsoft.com/downloads/details.aspx?FamilyID=A08F6991-16B0-4019-A174-0C40E6D25FE7&displaylang=en

Windows CE 5.0: Standard Software Development Kit (SDK)

http://www.microsoft.com/downloads/details.aspx?familyid=FA1A3D66-3F61-4DDC-9510-AE450E2318C3&displaylang=en

Windows Mobile 6 Professional and Standard Software Development Kits Refresh

http://www.microsoft.com/downloads/details.aspx?FamilyID=06111a3a-a651-4745-88ef-3d48091a390b&DisplayLang=en

Windows Mobile 5.0 SDK for Pocket PC

http://www.microsoft.com/downloads/details.aspx?FamilyID=83a52af2-f524-4ec5-9155-717cbe5d25ed&DisplayLang=en

Windows Mobile 5.0 SDK for Smartphone

http://www.microsoft.com/downloads/details.aspx?FamilyID=dc6c00cb-738a-4b97-8910-5cd29ab5f8d9&DisplayLang=en