The answer is that it depends.  The short answer is that the more recent the debt is the less likely it is that it will be dischargeable.  The more detailed answer requires analysis of a series of qualifications.  First, to be dischargeable, the tax debt must be at least three tax years prior to the time the debtor files for bankruptcy.  On March 13, 2012 a 2008 tax debt is not dischargeable.  After April 16, 2012 a 2008 tax debt may be dischargeable.  (Note, generally taxes must be filed by April 15, however, this year the date falls on a Sunday so taxes will need to be filed or postmarked by April 16, 2012.) 
If the tax debt is at least three years old, the next issue is that the tax return must have been timely filed, or filed at least two years prior to the bankruptcy.  This can become an issue where otherwise dischargeable taxes may not be dischargeable if returns are not filed on time.  If a debtor did not prepare a return for any given year and the IRS assessed a deficiency for that year the amount is not dischargeable unless the debtor files a tax return for that year.  However, if this applies to you, remember, that your return must be timely or must be filed at least two years prior to a bankruptcy.  The most simple concept to take from this is to file your tax returns on time. 
The tax return cannot be fraudulent in any way to be dischargeable.  If you were married at the time and there was fraud that you were not a part of there may be some options for you to pursue with the IRS regarding the debt.  Taxes are not dischargeable in any event where the taxpayer is guilty of any intentional act of evading tax laws. 
When filing for bankruptcy, if you are required by law to file a tax return, you need to have filed your returns for the previous four years.  If for some reason, i.e. unemployment, you are not legally required to file you will be excused of this obligation in the bankruptcy, but will still need to provide a copy of your most recent tax return.
If you have questions about whether your taxes are dischargeable, make an appointment with a St. Louis Bankruptcy Attorney today!