Since it seems to be a popular series I wanted to consolidate links to all my TMG Publishing articles.
As you may know they are designed to be a very simple walkthrough to get you started, the in no way cover every scenario but it should be enough to get you started.Then once you have it working, backup the config and tweak to your hearts content 
, Have fun securing exchange.
- OWA
- EWS\Outlook anywhere
Alternate method without pre-auth: using the same listener as OWA - Active sync
- SMTP
- Front-End \ Back-end TMG
- Ehlo article and Detailed white Paper From Greg Taylor.
Great series you’ve put together there, very useful for us as we see more customers moving to TMG. Considered consolidating them into a PDF, maybe put it on Scribd?
Thats a good idea, ill look into it