My buddy and colleague Natalya Voskresenskaya has been doing some kick ass posts recently on FAST Search. If your not familiar with this technology I would highly advise you pay attention to this in the coming months as it will soon become a common term used by your enterprise clients.
Natalya is doing some decent spin ups on this. Some of the posts published recently are:
Part 1 and 2
FAST search engine for SharePoint PART 2 (Overview of FAST)
Why Fast
FAST search engine for SharePoint PART 1 (Dictionaries)
FAST as SharePoint search engine
Enjoy