Building Scala from the source code is an rather simple process. The Ant [1] tool is used to control the build process of the entire Scala distribution: you can use any platform that supports Java [2] to build Scala and to contribute to the development of the Scala platform. You need to have a full install of Ant on your machine; if you use Ubuntu, you may need to install the package "ant-optional".
A machine with at least 1 GB of physical memory is strongly recommended. To build Scala, just type in the following command
$ ant
You can run the Scala test suite by issuing the following command:
$ ant test
If all tests complete successfully, you're in business: you can start using your newly build Scala system, and you can also start participating in the development [3] of the Scala language.
Links:
[1] http://ant.apache.org/
[2] http://java.sun.com/j2se/
[3] http://www.scala-lang.org/node/214