I have heard it's not legal starting from 2013. I also heard they postponed applying this?
So what's the deal? Allowed or not?
It has always been illegal and people have been arrested for smoking it in the open. I always love the faces of the tourists being arrested at Schiphol airport or in front of the Central station in Amsterdam for smoking weed. It is a global misconception that in Amsterdam it is as free as smoking cigarettes on the street. The principle has always been, what is called "Gedogen", which means that it is tolerated as long as you don't use it in the open and don't create annoyances. It is the Dutch way of dealing with social problems. It is similar to the so-called "afwerkplekken" for street prostitution. These are designated area's where street prostitution is tolerated. When ever there is a social problem that is hard to eradicate, the Dutch approach is encapsulate it in known zones, relieving other area's from problems related to that social problem.
In the seventies the Dutch government introduced so called "coffeeshops", which are designated establishments where cannabis use is tolerated. Again recognize the difference between tolerated and allowed.
What has changed recently is the legal status for these coffeeshops. They are now only allowed as a member-only organization for local residents. To get access to a coffeeshop you need to register as a member providing proof you live in the same city. The change of this regulation was guided by the pressure from Belgium and Germany. Border cities like Maastricht, Roosendaal, Terneuzen were like magnets to weed smokers from France, Belgium and Germany, causing problems in those cities and the surrounding countries. This was the reason behind introducing the member-only requirement for coffeeshops. This is also why the weed-pass as it is informally called was first introduced in the border regions and later imposed on other cities like Amsterdam. As Mark already said, again some cities like Amsterdam chose not to spent resources on enforcing this. Border cities did introduce the legislation to require the member-only status of coffeeshops, with the effect that most coffeeshops did close.
The law making it illegal, for foreigners, DID come in, and still stands.
However, due to all the controversy, it's changed now and is up to each city to decide how to apply it.
As a result, "coffee shops are OPEN in Amsterdam".
For a great read on the reasons behind the law, the effect, and the changes to the tourism industry as a result, have a read of Haze clears over Dutch cannabis law.
Other news articles as well indicate that:
The mayor of Amsterdam has made it clear that tourists there would still be granted access.