well as of the startup things, i am going to refer you to here:
short article on startup apps
as of the superkaramba thing, i have not yet successfully set this up to start automatically, although it is possible....whenever i tried to set this up in the .xinitrc, if i had it before the exec gnome-session then superkaramba would be the only thing to launch, if i had it after exec gnome session then gnome would start and karamba wouldn't, so i got fed up and just wrong a little script and put a icon link to it on my desktop so when i double click it, the 4 karamba themes i use will load...