Sort of a difficult question to answer ... I think it all depends on your learning style.
I learned LISP in my A.I. and Expert Systems classes in college, but that's how I learn ... I'm not a great book learner, I prefer to have someone explain it to me in a class setting.
LISP is definitely a unique language and it requires a new train of thought if you're used to conventional C, Java, PHP programming.
Best of luck to you !