In an effort to use more public transportation, I tried to get the general picture of the different networks. There are many different companies and organizations, institutions and information websites, but none of them provides a simple overview. The service of the "Mobilitéitszentral" is interesting though, as you can simply phone their hotline ( 2465 2465 ) and consult specific timetables here. There is another similar service online by Sales Lentz ( a transportation company ), which seems to be more general.

But this is only useful for people with a plan and a general knowledge of Luxembourg. Spontaneous decisions, tourism and going out is not really compatible with this system. So, for everybody that is used to public transportation in larger cities, with simple maps, here is a summary of bus maps in the main cities and around the countryside.

Online map of Luxembourg city buses

Only keep in mind this warning: Sundays you better stay where you are, or take a trip by foot... If you're very ambitious you can work yourself through the timetables and read all the footnotes beneath, otherwise you will get stuck on a station. 

You can mostly rely on the maps I uploaded. Missing plans (which is not due to my lack of searching) are the CFL trains and buses (Once there was one, but somehow the concept of simple plans is not hip anymore), the regional buses (RGTR) and international buses. If anyone finds up-to-date versions I'll be happy if you could send them.

I will try to keep these maps updated. I will not link them, these are actual copies, as the different websites are changing too often and mostly put the maps in larger pdf files. Thanks for understanding.