Hello Leonardo,
KDE still hasn't be accepted in Google Summer of Code this year. However here are some useful information:
However, I think it's better if you discuss your idea with the Kig team (which is part of KDE Edu), maybe creating a draft of a project proposal,
and, if well suited, post it on the KDE GSoC 2013 idea page on the kde wiki. [11]
My personal advice is to write to their mailing list and/or ask and discuss on IRC channel, keeping in mind that kde could still not be accepted to GSoC 2013.
Regards,
Claudio