How do I send e-mail using Gmail's SMTP and Indy 10?

问题

I'm using Delphi 2009 and the lastest Indy 10 from svn to send e-mails using SMTP, but it doesn't work with Gmail (Google Apps hosted domain). When I try to send an e-mail I get "Must issue a STARTTLS command first".

I tried Googling about it and I found several forums and several solutions, but they all just bashed some code or just said I needed an OpenSLL DLL, which so far isn't very clear to me exactly what I need.

Can someone please tell exactly which DLL I need and what do I have to change in the my TIdSMTP and TIdMessage objects in order to send the e-mails through Gmail's SMTP server?

Also, an explanation about why this authentication is different and what the DLL is for is very welcome.