Is there somewhere a good source of how to organize larger Arduiono projects?
However to get them compiled you still have to #include any .h files from the main .ino file (not quite sure why as surely their presence in the directory should be enough?).
I just want to point out that you don't literally have to create the tabs. Close the sketch. Copy any extra .cpp and .h files into the sketch directory (alongside the .ino file). Re-open the sketch. All the new .cpp and .h files are automatically turned into tabs in the IDE (and considered part of the project).