BBC Have announced the official air dates for Doctor Who in the UK and in America. 

UK:
UK Readers, the series will air Episode 1 on BBC One (Nationwide) on Saturday April 23rd around 6pm-7pm and also a new rumor that Episode 2 will be broadcast on Sunday April 24th. Followed by a six week run of the series. Then the series returns in September 2011.

USA:
US Readers, the new series will air at 9pm on BBC America on April 23rd 2011. No rumor that it will broadcast Episode 2 the next day have come around for the US. But stick with us for more details!