Hi and welcome to Just Answer!
Because you are waiting so long - there is definitely an issue - either with your tax return or with the IRS system.Unfortunately - contacting the IRS is the only way to clarify and have your tax return processed.
Most likely your tax return was assigned for review to an IRS employee and for some reason the review was not completed - you might want to find out the name and contact information of that employee.
Besides calling the IRS - you might want to visit a local IRS office - and discuss - please find locations in your state and verify which is more convenient for you - http://www.irs.gov/localcontacts/article/0,,id=98337,00.html
Another option is to contact the Taxpayer Advocate Service at 1-877-777-4778 during business hours. Alternately, you may complete Form 911, Request for Taxpayer Advocate Service Assistance - http://www.irs.gov/pub/irs-pdf/f911.pdf and mail it -
949 E. 36th Ave., Stop A-405, Anchorage, AK 99508or fax -(NNN) NNN-NNNN/p>
A list of Taxpayer Advocate Service offices can also be found in Publication 1546 - http://www.irs.gov/pub/irs-pdf/p1546.pdf .You may request that an IRS employee complete Form 911 on your behalf.
TAS can help if you can't resolve your problem with the IRS and:
---You have tried repeatedly to contact the IRS but no one has responded, or the IRS has not responded to you by the date promised
See here - http://www.irs.gov/taxtopics/tc104.html
Another option would be to have a local CPA or Enrolled Agent to represent you with the IRS. Your representative would review your tax return and might spot some issues that might resulted in delay and will discuss with the IRS these specific issues.
Sorry - as long as we do not know what is the issue - it is impossible to plan any actions. I home recommendations above would be helpful.
Let me know if you have any concerns.