Creating a good 3D model in 3D Studio MAX is hard enough. Now I've got to model clothes onto them too? Why can't all 3D game characters be naked?
Once you've resolved that debate in your head, watch this video. It will show you how to use the Reactor cloth system within 3DS MAX to model a basic cloth object, and then how to attach that cloth object to a deformable object. Now you can make realistic hair and clothes for your models, making them much closer to ready for use in a non-porn game.