The season starts airing on Saturday 19 April on BBC America in the USA. BBC-3 will show the series in the UK, probably in August. BBC-3 is shutting down at the end of 2014, so the fate of later seasons (if commissioned) over here remains uncertain.
Here's also a fun theory proposed by SpaceChampion on the Westeros.org message board:
Interesting, though of course it doesn't entirely fit. Danielle Fournier and Janika Zingler (two of the dead clones) don't fit onto the scheme, and it requires the use of Beth's nickname rather than her full name (Elizabeth). Sarah not fitting is more explainable: her name is not the one she was born with, so that name might be the one beginning with N, P or O. 'Leda' is taken from the trailer, and may be the name of another clone, the possibly-mythical progenitor of the clones, or indeed Sarah's real name.