Who was the first person to fly a powered aircraft across the English
Channel, from England to France ?

Dear kemlo,

The first person who crossed the English Channel in a motor-powered
aeroplane from England to France was Charles S. Rolls on 2 June 1910:

"On June the 2nd, 1910, the third Channel crossing was made by C. S.
Rolls, who flew from Dover, got himself officially observed over
French soil at Barraques, and then flew back without landing.  He was
the first to cross from the British side of the Channel and also was
the first aviator who made the double journey."

However, he was only the first pilot crossing the Channel in that
direction. Before him, two other aviators already crossed the English
Channel starting in France and landing in England: Louis Blériot (25
July 1909) and Jacques de Lesseps (earlier in 1910):

"No record of early British fliers could be made without the name of
C. S. Rolls, a son of Lord Llangattock, on June 2nd, 1910, he flew
across the English Channel to France, until he was duly observed over
French territory, when he returned to England without alighting. The
trip was made on a Wright biplane, and was the third Channel crossing
by air, Bleriot having made the first, and Jacques de Lesseps the
second."

Source:

Book Rags: A History of Aeronautics, by E. Charles Vivian
http://www.bookrags.com/books/haero/PART15.htm

Search terms used:
flugpionier ärmelkanal
://www.google.de/search?hl=de&ie=UTF-8&oe=UTF-8&newwindow=1&q=flugpionier+%C3%A4rmelkanal&meta=
"third channel crossing" 1910
://www.google.de/search?hl=de&ie=UTF-8&oe=UTF-8&newwindow=1&q=%22third+channel+crossing%22+1910&meta=
"second channel crossing" aeroplane
://www.google.de/search?hl=de&ie=UTF-8&oe=UTF-8&newwindow=1&q=%22second+channel+crossing%22+aeroplane&meta=

Hope this answers your question!
Regards,
Scriptor

Great .. Too many books do not say who came second.