You can join now, with the full version coming later this week.
From the release:
Record your Fantasy battle details, notes and report links online, create your own leagues, be ranked against peers, join alliances and fight for accolades and points in campaigns.
With stacks of Warhammer Fantasy stats!
Going LIVE by 31-Aug -2013 (join now)
o Record your battle details, notes and links & review or download them whenever you like
o Compare your battlefield performance and get ranked against fellow gamers
o Create leagues for up to 20 players
o Join an alliance and compete in a campaign for accolades and points
o Compare each army's performance against every enemy
o Check out the best units, troop types and phases for all armies
o Find out which armies are collected most, wanted, painted, loved and feared
o Read The Book of Grudges!
FREE to use, with no catches and no spam ! (I built it to learn how to program and for fun - not for the money)