In late April 2010
Series 5 will probably air around Spring 2010.
Matt Smith plays the Eleventh Doctor in Series 5
Actually, there are going to be 14 total episodes this series. The first part (of 5 episodes) has just concluded, the Christmas episode will introduce the Doctor's new companion, and the rest of the season will air in 2013 sometime (no set air date yet).
Sunday, 18th of April. Probably the same time and channel as last season.
No Jack is not in series 5.
series 5
No she was not in series 5.
spring 2011
There will be no Doctor Who series in 2009, instead there will be four specials, the first of which will air on BBC1 on Easter Sunday. There will however be a new series in 2010.
David Tennant will continue as The Doctor for the several specials which will be shown during the 2009 period. Matt Smith began filming as The Doctor on 28th July for series 5, which will air in 2010.
Series 5 on TV just ended. No date yet for TV series 6 Sorry, but no info for series 5 on DVD