I need to be able to remotely control a Mac from another Mac through a direct cable connection. Does anybody know a software that would do it?

Mac 1 - Host
OS X 10.4
Intel processor

Mac 2 - Remote
OS X 10.4
Non Intel processor

Mac 2 needs to be able to control Mac 1 and Mac 1 also needs to have full control of the mouse/keyboard at the same time. It needs to be direct cable because the processing that will happen on the Mac cant be interrupted and neither can the connectivity between the machines. Thanks in advance!

Jamie