I have started learning about Windows 8 Store Apps.
I recall from Silverlight and WPF programming earlier that people adapted the MVVM concept and now I am not sure if
Nope MVVM isn't dead and is still pretty alive!!!
ColinE defintion of MVVM resumes it pretty well. Indeed MVVM is basically a design pattern, and is not dependant to a specific framework.
Using MVVM is not a dogma..., though most who worked a lot with XAML app programming [WPF, Silverlight, WP 7 and WinRT...] will agree that MVVM truely facilitates a clear SOC separation of concern, between the development of the GUI and back end logic.
I've personally used Laurent Bugnion's MVVMLight package from Nuget in combination with WinRT, though you're free to use any other MVVM package or option you feel at ease with.
If you need further sample refs, I would invite you to have a look at the following recording of a webinar on 'MVVM in Windows 8 Store' by Gill Cleeren
http://www.silverlightshow.net/video/MVVM-in-Win8-Webinar.aspx