Yes - can use simple membership with webforms, as described in: http://blog.osbornm.com/2010/07/21/using-simplemembership-with-asp-net-webpages/ and http://www.mono-software.com/blog/post/Mono/226/Adding-ASP-NET-SimpleMembership-to-an-existing-MVC-4-application/
I am using in an Azure Cloud Service that ran fine locally, but ran into problems when publishing to the Cloud. This was resolved by removing references to WebMatrix.Data and WebMatrix.WebData (v2.0.0.0 manually added as per 2nd link above), then adding NuGet Package Microsoft.AspNet.WebHelpers to the project. This added references to v3 of WebMatrix with Copy Local = True. Downside is the NuGet package includes a load of other stuff that I don't actually need.
Hope that helps.