Quite a few people have asked me about the location of the remnants of Hitler's bunker. Hitler's bunker was in or rather under the garden of the Reichskanzlei (1), which was at 77 Wilhelmstraße, in the area where most of the government buildings were. There were several underground passageways and other, smaller bunkers in this part of Berlin (one of which -Leibstandarte Adolf Hitler's bunker- has been discovered only recently, when work was being done for Roger Waters' "The Wall" concert).
There's nothing left of the Reichskanzlei (it was levelled by the Russians), so the exact spot may be difficult to find. The bunker was located at the marker on the map, away from the Wilhelmstraße (which only recently reverted to its pre-war name) in the direction of the Goeringstraße (now Ebertstraße) and not far from the Voßstraße. It had a stairway leading to the Ministry of Foreign Affairs (2) which was at 75 Wilhelmstraße.
In May '95, the regional parliament of Berlin decided to lock up the remnants of the bunker and build houses for representatives from the Bundesländer on top of it, rejecting a proposal from the Grünen/Bündnis 90 to retain it as a monument. More recently, the location was marked with a plaque explaining the layout and construction of the bunker.
Most of the bunker (the entrances and parts of the bunker) has been destroyed, some of it by the Russians right after the end of the war, but there should be quite a bit left from the actual Führerbunker, which was 15 meters underground and protected by meters of concrete.
For a picture of the surroundings (not necessarily the exact location of the bunker) taken in '95, look here. More information on the location of the bunker and the bunker itself can be found here, and, of course, on Wikipedia. These also have very exact maps of the location.
To see what the bunker looked like inside, have a look at the virtual reconstruction that was made by Christoph Neubauer.