PGP and other encryptions methods for PHP

I need to encrypt data in an application then mail it to a recipient where the email client must decrypt using a private key. The recipient would be using MS Outlook or another email client perhaps Eudora. What encryption techonologies are best for this? I had a brief look at OpenPGP but not sure of how well that integrates with PHP. Any help or tips from anyones who's done some work with this would be appreciated. ======================= Ron Dyck WebbTech www.webbtech.net