I used a little script I wrote in an attempt to roughly convert most of the snippets from the CakePHP TextMate bundle into Vim's snipMate format. After some cleanup, they appear to work just fine.
Put cakephp.snippets in your snipMate/snippets directory, start Vim and tell snipMate to load them:
:set ft=php.cakephp
If you want this to always happen add au FileType php set ft=php.cakephp to your ~/.vimrc. If you do this, keep in mind the CakePHP snippets will be available for all PHP files you edit.