The IRS has released a draft of the 2012 version of Form 706: United States Estate (and Generation-Skipping Transfer) Tax Return Estate of a citizen or resident of the United States - draft as of 08/16/2012.
The 2012 version of Form 706 differs from the 2011 version in that it contains a separate section called Part 6 - Portability of Deceased Spousal Unused Exclusion (DSUE). This section should be completed by the surviving spouse of a 2012 decedent who is electing to make use of the deceased spouse's unused federal estate tax exemption, or by the surviving spouse of a 2012 decedent who wants to specifically opt out of making use of the decedent's unused federal estate tax exemption. The 2011 form did not have a check-the-box, opt out section with regard to DSUE, instead a statement had to be attached to 2011 Form 706 indicating that the estate was not making the election under section 2010(c)(5) or by writing "No Election Under Section 2010(c)(5)" across the top of the first page of 2011 Form 706.
The 2012 version of Form 706 should be used for decedents dying after December 31, 2011, and before January 1, 2013. The final version should be released in the next few weeks since the first returns for decedents who died on January 1, 2012 are due on October 1, 2012.