Client-Side Email Send Util (Browser Plugin?)

We need a simple tool that will retrieve outgoing messages from our server and send them out from a _client's_ / subscriber's computer (IP address). I'm not so experienced with client-side-code, but perhaps this could be a browser toolbar or plugin? Java? I don't care too much _how_ it works, just that it does, and ideally, run on both PC and mac though the vast majority of our clients are on Windows. Perhaps something like Google Desktop? The client-side system will just just need to store a subscriber's login and password, and a subscriber's local SMTP settings, that's it. It'll then retrieve (say, 1x per hour, staggered so all systems don't check at the same time) any messages (encrypted XML? serialized php? whatever you recommend) from an outgoing queue for that client/subscriber, and send them out. Our CRM contains a sophisticated autoresponder, but our IP address is getting trashed because some subscribers use it too liberally and get spam complaints - however few they are, it is enough to cause problems with our internal system emails going out - so we'll just make subscribers use their own accounts, and if they get busted for spam by _their_ ISP, it's their problem. It would also be nice if (separate project?) the system could tie into our CRM's calendar and just notify the client/subscriber of upcoming appointments like Outlook. I'm open on the how, as long as it works. Thanks! Roger P.S. please advise what programming language you plan to use when you bid, also, what format you want the outgoing messages in. ## Deliverables 1) All deliverables will be considered "work made for hire" under U.S. Copyright law. Employer will receive exclusive and complete copyrights to all work purchased. (No 3rd party components unless all copyright ramifications are explained AND AGREED TO by the employer on the site per the worker's Worker Legal Agreement). ## Platform unsure... C++? Browser Toolbar? Adobe Air? Whatever works.