Sources and links
dutchFS site nl.2000.com simaviation.com flightsim.com calclassic.com HJG Group Classic British Flight
The Dutch Flight Simulator Site. On this site you will find beautiful repaints of Dutch registered planes plus additional software for panels and scenery. On the forums you will find a lot of tips from your fellowpilots.
The default scenery of The Netherlands and the Dutch airports in Flight Simulator is not great. A group of Dutch volunteers has improved and modified the default software and are still developing it. On this site you can download a realistic scenery of Holland and the Dutch airports
One of the most complete websites for Flight Simulator. If you cannot find it here it likely does not exist.
I would say, second best. I like their convenient searching machine.
California Classic Propliners. The site for the American propliners
The website for the first and second generation jetliners plus panels, sounds and repaints.
Again a group of volunteers. The most important British airplanes you will find here.
For repainting you need models. Many sites have freeware. Below the sites from where I download the most.
next next Luchtvaartregister
On this site of Herman Dekker you will find all important information of aircraft which ever are registered in the Dutch civil register. This site is only in Dutch.
KWJ’s  Luchtvaart & Modelsite
This site is for builders of scale models. You will find here all information about planes, liveries and colors of all the aircraft which are or have been in service with the RNethAF and the Dutch Naval Service. A very useful site for repainters as well. This site is only in Dutch