A great site to download airport diagrams and other charts is charts.aero .
As of April 2015, however, the site seems gone.
Airport diagrams show all the taxiways and ramps, which is what you are looking for.
Keep in mind that this is an unofficial website.
The charts should not be used for actual navigation.
aviation.stackexchange.com/users/4/Philippe Leybaert
In the US, you can find this on the FAA's website here .
You can search for a US Airport, and it will pull up a Airport diagram with Taxiways, Runup areas, and Runways on it.
I couldn't find an official guide for European airports, but this site has a detailed guide for CDG , among others, with a taxiway map being one component.
They also have a similar guide for AMS .
They do not have one for PRG.
Keep in mind these are unofficial charts.
As Lnafziger noted, this site also has airport charts, including approaches.
The downside is you must register (free) first to access them.
You can read more in this answer .
aviation.stackexchange.com/users/774/SSumner
If you look up the ICAO code, e.g. here http://en.wikipedia.org/wiki/International_Civil_Aviation_Organization_airport_code
then Google for the code
+ charts, e.g "EGLL charts"
, you will usually find what you're looking for. https://www.google.co.uk/search?q=egll+charts
aviation.stackexchange.com/users/595/Simon
Airport ground charts are always part of the AIP (Airport Information Publication).
They are usually publicly available in electronic format, but not always easy to find.
Wikipedia's entry for AIP has a For european airports, you can get them from Eurocontrol (requires registration).
However, you can also usually get these directly from the country's CAA or AIS.
Here's the ones you asked for (be aware these links may only work for a short period of time): Paris CDG .
Amsterdam Schiphol .
Prague .
aviation.stackexchange.com/users/1128/molgar
Just stumbled across this directory, hosted by VATSIM.
Doesn't appear to be entirely up to date but does provide a link for charts for Prague, among many others.
(Includes links to content that may be behind a paywall though). http://www.vatsim.net/charts/
aviation.stackexchange.com/users/790/Thunderstrike
Whenever I sit in an aircraft and we taxi around the airport, I wonder how exactly is the airport organized, for example, the arrangement of the taxiways and runways.  Is it possible to locate airport diagrams? I'm mostly interested in Paris CDG, Prague PRG and Amsterdam AMS.
Are the airport "taxi" plans available online?
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<airport><taxiing><eu>
aviation.stackexchange.com/questions/1539
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A great site to download airport diagrams and other charts is  charts.aero. You can also find airport diagrams that show all the taxiways and ramps.  You can find such information on charts.aero, on the FAA website or on the individual airports websites.
There are a number of places where this information can be found.