I started a project like this once, but never finished. Contact me if you want my incomplete "Perl to Python phrasebook." My goal was to help unfortunate Perl programmers migrate to Python.

One thing to look out for: things that are functions in some languages are syntax in others, methods in others, and complicated recipes in others. You need to give people sample code. For example, look at how each language wants you to express "length of an array/list:"

Python: numbers = [4,8,15,16,23,42] print len(numbers) # yields 6

Perl: @numbers = (4,8,15,16,23,42); print $#numbers + 1; # yields 6 # or... $numlen = @numbers; print $numlen;

Not really a "function" at all in Perl.