GaussMem
The program GaussMem to compute the memory requirements for Gaussian 09 calculation is available here.
GaussMem calculates the required amount of memory to be used depending on the number of shared processors, the number of basis functions, the type of functions and the nature of the calculations.
GaussMem is a cross-platform command-line utility compiled for Windows, Linux (64 bit) and OS X. It has been coded in PureBasic and is freely distributable for academic or personal use.