INTRODUCTION
The Atacama Large Millimeter Array (ALMA) is an interferometer being built on the Atacama plateau in Chile, working in the millimeter and submillimeter range. It will be a world-class facility and is intended to be useable by astronomers from a wide community - including non-radioastronomers. To make that more than wishful thinking, it is essential to provide tools allowing (almost) anyone to test how his or her favorite source would look like should they decide to ask for observing time.

This is where instrument simulations come in, and there are many of those :

There is an ALMA and ACA (ALMA Compact Array) simulator provided with the GILDAS software from IRAM. Up-to-date instrument configurations in the right format are provided below (thanks to Jérôme Pety and Ian Heywood).
The CASA software from NRAO is the intended suite for operating ALMA. It also features an instrument simulator.
As part of my PhD, I wrote a very crude simulator in IDL. Contact me if you wish a copy.

For more information on ALMA

alma-GILDAS-cfg-2010-06-02.tar.gz : ALMA and ACA configurations for the GILDAS simulator.

Simulated observation of low-mass dense cores
Below are examples of simulated observations of the dust continuum emission from low-mass collapsing cores at 150 pc, observed with the full ALMA array in configuration 15 at 144 GHz (band 4), using a 8 GHz bandwidth. Colour scales indicate brightness in Jy/beam and the contours correspond to the sensitivity limit (14.55 μJy) in this band, out put by the ALMA Sensitivity Calculator. Shown are different magnetization levels, from MU2 (strong magnetic field) to MU200 (quasi-hydro case) and different viewing angles. This is work done in collaboration with B. Commercon, to be submitted to A&A.