ARBBL

http://vanguard.easyarmy.com/

This is the unofficial 'official' online army builder for Vanguard (linked to on the Mantic page).
It seems that there are some stats/units on there that aren't in the book or in the pdfs, but have come from stat cards that are in 'faction sets & boosters', and they are official.

Mantic have stated that this is the official way to get all the rules for people who already have models and can't get the cards without buying more. The intention is that everything will be on here.