For Chapter 13, the rule on tax returns is that you have to have filed the tax returns that you were required to file for the years ending in the 4 years before the filing of the petition. For example if you are filing in 2009, you would need to have 2005, 2006, 2007 & 2008 filed. If you are on extension for 2008 then you wouldn't have to have that one filed until the extension runs out.
This can be a pain and significant expense. As you may have heard Congress revamped the bankruptcy laws in 2005. This Chapter 13 tax return requirement was added then. It has been criticized because bankruptcy filers have to spend money on tax preparation fees that otherwise could be used to pay the unsecured creditors. But it is the law and neither the judge nor the trustee have the power to waive the requirement.
There is no such requirement for Chapter 7 filers. But you do have to submit your last tax return to the trustee.