Is there a way to explore the unconscious?

Go to sleep. Dreaming is one way. Or read Freud’s Interpretation of Dreams.

There are many ways. Meditation is certainly a good one. If you are interested in the neurophysiological aspect you may try reading “The Synaptic Self” by Joseph LeDoux.

Do something creative every day. Writing is how I do it.

If you’re interested in the unconcious, look into books on Freud and Freudian psychology. Soethe6 is right, Freud believed dreams were an outlet for inappropriate or suppressed aggressive/sexual urges. He developed a theory about latent and manifest content.
I can’t recommend any specific books about it, but there are hundreds out there.

Keeping a journal of your dreams is a wonderful way to know what your really thinking underneath. Also try to track your impulses, or your “gut instincts.” Often we act out of our subconcious rather than some magical intuition.

I’m currently working on my graduate thesis on psychoanalysis, and, just as soethe6 and omfgTALIjustIMDu said, psychoanalysis and freudian psychology study the unconscious.

You should also note that the freudian unconscious it’s not the same unconscious that the linguist’s, or even jung’s unconscious, and that acually the idea of “the unconscious” is prior to Freud, but he is the first that linked the unconsciuous to the sexual trieb and repressed memories. If you really want to study the freudian unconscious, you should stick to Sigmund Freud’s work, specially his writings from 1915, that are commonly known as “the metapsychology”:

1. Instincts and Their Vicissitudes (1915)
2. Repression (1915)
3. The Unconscious (1915)
4. A Metapsychological Supplement to the Theory of Dreams (1917 [1915])
5. Mourning and Melancholia (1917 [1915])

The most serious way to read these articles is from the “Standard Edition”, translated by James Strachey. There are lots of other editions and translations, many of them are just pathetic.

hallucinogenic drugs are a wonderful way to explore your inner being, if your into that sort of thing that is.