Scott Klarr has pulled together a listing of the top cheat sheets that he's found out there relating to PHP (and things surrounding it) like:

• this one from blueshoes.org
• a sheet covering filtering and escaping
• a Smarty cheat sheet
• a few covering WordPress
• and ones covering CakePHP and Drupal

Check out his page for more (and thumbnails for each).

Robert Kline has a handy little cheat sheet to translate Perl to PHP or vice versa. It's been quite some time since I had written any Perl, besides a quick parser or two. This certainly does the trick for me in getting my thinking correct for the Perl syntax. I would assume Perl hackers would say the same thing when needing to use PHP.

The sheet goes through things like arrays, array split/joins, string comparisons, HTML elements, and MySQL database access. Obviously, it works the other way around too, allowing PHP programmers to get some of the basics of Perl...