If you want to get there from the real world, fly on the plane to Yumland, go find the statue of the four ladies standing together, then jack into it. After that, talk to the purple Navi in the comp and make a donation. He will give you the password to the cube. If you want to get there from the net, get to Netopia area, then head down and to the right. That should lead you to the arrow that leads to Yumland.
no you can only link megaman games together if it is the same number like megaman battle network 3 blue to megaman battle network 3 white
you buy it
The final boss of Megaman Battle Network 4 is Duo. It does not matter which version you have. However, after defeating Duo, there are optional bosses.
currently there isn't any info about Megaman Starforce 4 , but there will be a crossover game with Megaman Starforce and Megaman Battle Network for the DS
Blue moon or red sun?
no
yes but you must use a cable
people with heads
it is in the tree by the pink squirl
4-d x-dragon ninE
some where in castillo area from the net
The NebulaCD is used for opening the doors with the skull on it at the Net.