Karma is more a Buddhist concept than a Hindu one (many Hindus don't accept the concept at all and those who do feel it is of secondary importance) and Buddhism is more of a philosophy than a religion, being more akin to humanism - our duty in life is to do as we would have done to us and try to become as close to the "ideal" person as we can. As a Wiccan I blieve whole-heartedly in the law of 3-fold return - it may not happen in this life, but sooner or later our thoughts, words and deeds, whether for good or evil, will rebound on us.