Yes, he returned (and with Gwen and Ianto from Torchwood) in the Series Four finale two parter.
Captin Jack is a fictional man, from the BBC series Doctor Who and Torchwood.
Yes, Captain Jack Harkness asked the Doctor about what happened to Rose Tyler after she was trapped in a parallel universe. The Doctor informed Jack that Rose was safe and happy in the parallel world with her family.
John Barrowman played captain jack in doctor who. :)
It's Harkness, although that is not his real name, he stole the identity of the real Captain Jack during WW1. His real identity is unknown.
No Jack is not in series 5.
Captain Jack had a relationship with Ianto Jones in Torchwood. He's also kissed other people like Captain John who is his ex. On Doctor Who he kissed both the Doctor and Rose.
No, there has never been a young version of Jack in Doctor Who.
Jack is apparently omnisexual, he likes anything regardless of gender or species, which is apparent in Utopia when he flirted Chantho the blue insect woman.
In the episode, "The Empty Child." Christopher Eccleston starred as the ninth doctor. It was in season one, 2005. The companion was Rose Tyler, played by Billie Piper.
Captain Jack Sparrow!
At the moment there are no plans for him to return to Doctor Who.
The 9th Doctor, Jack kissed both him and Rose before going off to fight the Daleks in The Parting of the Ways.