You do not *have* to build your satellite assemblies by hand (using resgen
and al). You can, of course, which allows you to modify existing assemblies
or add new languages without having to rebuild everything, but the IDE can
certainly handle it for you!

All you have to do is add the .resx files for each language to your project.
Make sure you follow the proper naming conventions, i.e. <Base
Name>.<culture ID>.resx. The language neutral and fallback resources can
also be added as <Base Name>.resx. (These resources will be embedded in the
main assembly containing your code.) When you build your project, the
appropriate satellite assemblies (<Base Name>.resources.dll) will
automatically be created in the appropriate directories (culture ID)
underneath your output directory (bin/<Configuration>). You'll notice that
you won't have access to the .resources files this way (created manually
using resgen). They are created at compile time, of course, and then
embedded into the DLLs. However, they are not actually saved as separate
files.