there are a number of solutions that provide that type of capability... with varying levels of success, ease of use, support, and legality.

one thing to note... mouse passing won't work like you think it would. on the surface, most people think that if you can mirror the mouse clicks then your characters will all be in the same place. the problem is, there is no way to insure that the point of view on both characters is the same. in fact, it's just about guaranteed to not be the same... this is due to the position, orientation, zoom, and camera angle all varying... ending up with a different view port onto the virtual world... and your clicks end up in different points in that world. (even if you have a wireless mouse tuned to the same frequency across 2+ machines..)

there are some clicks that will pass properly... for menus, quests, books, action buttons and bags... but anything that goes through to the virtual world is a crap shoot.

i hope that makes sense.

in the meantime... check out keyclone, it should provide the shortest route from go to playing. (/shameless self plug)

if you have any questions or comments, please feel free to drop me a note.

Rob (keyclone developer)