- the package file does not contain a package.xml! (it should also be a tgz file)
- use HTTP_Request instead of fopen() (turning on allow_url_fopen is really asking for trouble)
- urlencode() should not be called inside the getter methods - they should return what was passed to the setter methods
- fix PEAR CS issues: spaces instead of tabs, if-else syntax, class declarations should also follow the "BSD/Allman style"
- use single quotes instead of double quotes
- the add() and remove() methods should give more details about the error condition - how about throwing an exception? (write your own class that extends PEAR_Exception)