What to Download

1. Download JetBrains MPS EAP (build #233) from:
http://download.jetbrains.com/mps/mps233.exe - windows version
http://download.jetbrains.com/mps/mps233.zip - other version

2. JetBrains MPS contains IntelliJ IDEA plugin and you need IntelliJ IDEA 5.0 to work with JetBrains MPS. Download the required IntelliJ IDEA build from:
IntelliJ IDEA 5.0

How to Get Started

1. Install the required IntelliJ IDEA build.
2. Install JDK 5.0.
3. Install JetBrains MPS.
3a. On windows run installer.
3b. On other system extract mpsXXX.zip and set path to JDK in mps.sh located under %MPS_HOME%/bin directory.
4. Start JetBrains MPS. JetBrains MPS will ask you to install JetBrains MPS plugin.
5. Start IntelliJ IDEA.

You will probably want to try the MPS Hello World tutorial.

Additional Information

Previous builds

h3 build #220
http://download.jetbrains.com/mps/mps220.exe - windows version
http://download.jetbrains.com/mps/mps220.zip - other version