First off, very nice code, clean and well documented and also tests! ;-) But, here are my reasons that make this vote conditional:
1) Don't use the PHP License (as it conflicts with GPL), please select LGPL or The New BSD License instead. I personally favour the latter.
2) Please create your own Exception class (extending PEAR_Exception - HTML_Entities_Exception).
3) You probably don't need another tests/examples dir here:
The second "tests" and "examples" is redundant. I think you can define this in your package.xml.
4) I think you need to define a replacement for @package_version@ in your package.xml. After I installed your package it still said @package_version@ in there.