Tools
Python is a scripting language that is easy to learn and use (like MATLAB), is object-oriented and very powerful, and is rapidly becoming a standard language for scientific scripting. Many scientists are developing packages and toolboxes in python, for example www-pcmdi.llnl.gov/software-portal/cdat, www.pyngl.ucar.edu, and countless other, smaller packages. Many utilities are being developed with python hooks build in (like VTK, a 3D visualization library). Python has all of the basic tools required for working with numerical model data, in particular NetCDF support. Python can also be used as a wrapper for C and FORTRAN code, so you can have the speed of FORTRAN for number crunching with the ease of a high level language for data I/O. Finally, python is free and open source, and is available on all major computer platforms.
A good place to learn about scientific computing using Python is http://www.scipy.org. You will need a few packages installed in order to work with ROMS output in Python:
numpy: http://numpy.scipy.org (basic numeric array mathematics) matplotlib: http://matplotlib.sourceforge.net (and the basemap toolkit for geospatial plotting) python-netcdf4: http://code.google.com/p/netcdf4-python/ (follow the install directions *exactly)
