[school-discuss] application sharing on line

[roberto <roberto03@xxxxxxxxx>]

hello,
i manage an after school course based upon geogebra (btw: i have
prepared some worksheets and i will publish them at the end of the
school, after the testing by my students );
unfortunately, some students cannot attend lessons so i would like to
follow their efforts via internet;

i need an application such that i open a geogebra window on my pc and
they can see my activity on theirs and ... viceversa !

i think it is something like desktop sharing or similar;
do you use any ? which ? is it useful for you ?

thanks in advance
-- 
roberto