"4.Integrating some existing services (google maps, youtube...) into site? "
If accepted into Google Summer of Code, I plan to work on Google Maps integration. After I complete that, I plan to write a tutorial on how to easily integrate it. :)
"it could be nice to have a tutorial how to create a picture-gallery using scriptaculous or one kind of ajax library ;-) "
"it could be so perfect...
just have a look here with Lightbox Js what is possible to do : "
I've integrated Lightbox into another CMS.
Here is an example of it in use:
Who knows, maybe after I finish the work on Google Maps, I could work on creating a Photo Album module for SilverStripe that use Lightbox. That'd be fun. :)
Well, I must go and do homework (my spring break is almost over).
I look forward to being active here in the summer.