Maildir Class

Hi! I'm writing a class for reading and delivering mail into Maildir folders for a project of mine. I'm trying to write it according to the PEAR rules, then it could maybe be included in PEAR as I couldn't see anything already present that can do this. I was wondering is it preferred that classes use 'resource IDs' in the way that the mysql_* functions and Mail_Mbox do at the moment to keep track of which Maildir is being edited, or could I use the class constructor to set the path to the Maildir and the user would simply instantiate new objects for each Maildir? Also, is there anything special I need to do to write a PHP5 compatible class? Does my class need to be PHP5 compatible for it to be suitable for inclusion? Apologies for these questions, but I've never submitted code to an Open Source project like PEAR before, and I've not been using PHP for that long. Cheers! Andrew