The word "Titan" has been mentioned many time already, but because it is still in its CTP3 stage, people who have been involved in the CTP3 have not been able to say much about the product due to agreements with Microsoft. That being said, there have been quiet alot of resources available online, which I thought I'd link into a single article.
CRM Titan Books:
Working with Microsoft Dynamics(TM) CRM 4.0
Programming Microsoft Dynamics(TM) CRM 4.0 Developer Reference
ISVs on Titan
Titan Screencasts from Phillip Richardson
On this particular blog from the CRM Team Blog, they give out very strong highlights of the features that will be part of 4.0 Titan.
Guy Riddle's Blog "Titan" NDA Lifted
Metro - CRM ISV Training (Only for ISVs enrolled into the Early Adopter programme)