Anybody know where I can find a book (not codex) on them? I am trying to get a better feel for my army and would like to read up on there where, when and why..

Don't know if this will help or not, but here is a wiki article that is pretty detailed about them:

http://en.wikipedia.org/wiki/Sisters_of_Battle

look for "faith and fire"

you should still be able to find it in most major book sellers

or click on the link below and order that moFo

http://www.amazon.com/Faith-Fire-Warhammer-000-Novels/dp/1844162893/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1218747364&sr=8-1

(don't know why the cover is so gimped up on there, it actually looks really nice)

There was also a comic book too. Demon something. Sorry can't remember the full title.

Thanks!!! I saw the comic book at Up, Up, and away, but that was clear as mud to me when I looked through it.

Here is the big collection one

http://www.amazon.com/Daemonifuge-Warhammer-000-Kev-Walker/dp/184154261X

Also, though it isn't a book, the 40K Dawn of War game Soulstorm focuses on the Sisters. It's stand alone, too, so you don't need the original game.

THanks!!! these are all awesome suggestions!!