The StarCalc Homepage
I cannot thank the creators of this program enough for the incredible work that went into it.  Until stumbling across this program I was at a loss as to the correct positions of the constellations back in ancient Mesopotamia.  If you have any interest in astrology, astronomy, or simply want to see what the sky looks like on any given night (AD or BC) in any place, I would highly recommend the Star Calculator.
Divinity School of the University of St. Andrews
A summary of the 'Book of Giants' from the Divinity School of the Univeristy of St. Andrews.
The 'Book of Giants' is a smaller but similar text to Enoch's writings.
Delerium's Realm
Delerium's Realm
A list of articles concerning the Watchers and Nephilim, including references in Biblical, Jewish, and Apocryphal literature.
A Dictionary of Angels
'A Dictionary of Angels: Including the Fallen Angels', by Gustav Davidson  (Amazon link)
The most comprehensive book I've found that deals with the names, purposes, and origins of the various angels.

Seven Angels
Seven Angels
A very interesting site with lots of information and fantastic artwork relating to the Watcher Angels. 
Seven Angels - Literary Resources
The Nephilim Library (within the Seven Angels website)
I'm including a separate link for the literary resources in the Seven Angels site just to make navigation easier.
Star Names in Translation
Star names in translation. 
A website including a compiled list of common star names and their translations.  This can be very interesting when tracking down the original associations of any particular constellation.   Further references and useful links are found at the bottom of this site.
Resources
Angelic Hierarchies

List of
Characters


Mesopotamian Astrology
The
Setting

Map of
the Grigori

Preview:
Chapter One

Resources
Contact