Download 
Cube Explorer 5.12 needs
128 MB of RAM and runs on all Windows platforms from Windows 98 to Windows 8 (32 bit or 64 bit).

The downloadable archive contains a version for the Quarter Turn Metric QTM (a 180 degree turn counts as 2 moves) and Half Turn Metric HTM (a 180 degree turn counts as 1 move). Cube Explorer was designed for the HTM and this is the version with better overall perfomance. So use this version unless you exactly know why you want to use the QTMversion. 
If you are
interested in an Optimal Cube Solver in the Quarter Turn Metric
which runs on the command line under LINUX and WINDOWS,
you can download the documented C source code here.
An already compiled version for Windows is available here.
The program also accepts the file format of Cube Explorer, so you can
generate your cubes in Cube Explorer and feed them to this program. 
A working version of the twophasealgorithm is not too easy to program. For demonstration purposes I wrote a Java package which implements the twophasealgorithm in its simplest form without any symmetry reductions. The package org.kociemba.twophase, the sourcecode and the corresponding javadocs are included in the file twophase.jar . The little Java program GUI_example.jar (Version 2009.02.16), which is an executable jar file shows an example how to use the package. The tables in this implementation take only about 5 MB and are generated within seconds. Nevertheless the package routine solved about 26000 random cubes/hour if the maximum maneuver length was set to 21 moves and about 800 random cubes/hour if it was set to 20 moves maximum length. You may use this package for free but you must include an appropriate credit line. 
Last but not least I implemented the TwoPhaseAlgorithm into a Mathematicapackage. The code runs very slow, but it is also very short. It might be interesting from a theoretical point of view. The interactive editor function in the package needs at least Version 6.0 of Mathematica. 