I don\'t know how to using dynamic master page in ASP.NET MVC RC 1.0. Please help!
There's a reasonably maintainable solution discussed on http://forums.asp.net/p/1394235/2991293.aspx where you create a common site master descendant and use that for all your own views. There's also a CodeProject entry that looks interesting that uses a custom ViewEngine at http://www.codeproject.com/KB/aspnet/ASPNETMVCDynamicThemes.aspx.
I need to do this too, but I haven't tried either solution yet so I don't have a feel yet for which is better overall. IMO, dynamic skinning is a crucial feature for MVC, particularly to cater to user personalization.