I recently had an EEG scan done, due to numerous headaches, dizzy
spells and mild memory loss which I am experiencing.  The doctor said
that I did not have seizures, but a seizure-esque problem explained to
me as "slowing" which was in the left temporal lobe.  I believe that
this slowing is a slowing of the brain-wave patterns in that region of
the brain, but I would like more information about this condition and
possible treatments or procedures to help the condition.  I was also
proscribed a medication called "Valproic Acid" in 250 mg form to be
taken day and night and would like some information about this drug,
specifically what it is designed to do or counteract.  Thank you.

The first part of your question, regarding the cause of temporal wave
slowing, is the harder one to answer.  In my experience, very few
non-neurologist physicians are comfortable interpreting EEG results. 
If you saw a neurologist, I would simply call and either ask for a
more thorough explanation over the phone, or schedule a follow-up
appointment to discuss it in person.  If the results were interpreted
by your primary care physician, ask him/her if a neurologic
consultation is in order.
The valproic acid (brand name is Depakene in the US) you were
prescribed is a common anti-epileptic drug, meaning that it is used to
treat seizures.  It has specific indications (i.e. approval) for
absence seizures and complex partial seizures, but is frequently used
in other types.  It's actions are thought to be caused by increasing
the concentration and/or activity of a neurotransmitter called GABA in
the brain.
Extensive drug information can be found in a pharmacology text (I used
Mosby's Drug Consult).  More general patient-oriented information can
be viewed at webmd
http://www.webmd.com/drugs/mono-19-VALPROIC+ACID+-+ORAL+CAPSULE.aspx?drugid=8885&drugname=Valproic+Acid+Oral

Good luck with everything.