For all levels:
If you like learning grammar, this website is your treasure! It’s translated in many languages and covers the whole Dutch grammar universe.
Dutch by Skype
There’s several ways you can learn Dutch via Skype. It’s handy since they can correct your mistakes directly. It’s also very flexible, but I’d recommend you stick to the same teacher when you find a good one. Find your teacher through Taaltutor, Taalservice-Utrecht or SayitinDutch.com.
Search for a group in your native language, or try this or this active group in English for Dutch learners. Post questions, you'll get free answers.
There’s a lot going on on YouTube, especially if you know what you’re looking for. For example, you can search ‘simple past in Dutch’. However, to really learn on a regular basis I wouldn’t recommend it. This search might get you started. Mind that those are usually not in the Flemish accent.
Learn the most used verbs and their conjugations with this handy website.
The public news agencies publish news every day. It’s excellent Dutch. Try to compare the news items with the news in your own language, so you already have a background. Here's the news with a Flemish accent and one with the Dutch accent.
Movies on YouTube
There’s loads of movies on YouTube you can watch with subtitles. It’s a great way to learn a language while being entertained. If your level is high enough, watch with subtitles in Dutch. Start your search here for Flemish accent films and here for Dutch accent films.
This website of the public news agency contains so many stile tips that only experts know.
The taalmail is an email you receive about every week with corrections on what the public news agency has produced.
Every year, there’s a big dictation (groot dictee) for Dutch speaking persons where you can participate in.
Put a comment if you see another source or a dead link!