This is a very interesting guide I have found to convert from PHP to Perl and vice versa. I find it pretty useful because many times I have to work with Perl and PHP together and run in confusion. The Perl/Php Translation is created by Robert Kline.
In the guide you can find conversion for arrays, hashes, data structures, array split/join, case conversion, string comparaison, functions, string matching operations, basename/dirname, environment variables, POST/GET parameters, HTML elements, URL encoding and mysql database access. This is not everything but that’s already things you might need for everyday coding.