Today, ArcGIS for Collector is available on iOS and Android devices, only. However, the image below is from some Esri video I watched earlier in the year. It appears that an ArcGIS for Collector app for Windows will be available some time in 2015. I look forward to this release.
Thank you Joe for the very useful input. We will be waiting till the release Collector for ArcGIS that is compatible with Windows OS