AgileMapper

AgileMapper is a zero-configuration, highly-configurable, portable object-object mapper with viewable execution plans via a static or instance API.

You can use it to create new objects:

var customerDto = Mapper.Map(customer).ToANew<CustomerDto>();

...perform id-aware updates:

Mapper.Map(customerViewModel).Over(customer);

...and merges:

Mapper.Map(customerOne).OnTo(customerTwo);

It's available via NuGet and licensed with the MIT licence. Check out the wiki for more information!