Your deceased parents ownership interest in the property received a step-up in its cost basis to the fair market value as of the date of death.
Thus, if your parent owned 50% of the property, then that portion of the property's cost basis (for gain calculation purposes on the sale) is stepped up to the FMV as of the date of death.
For example: If a married couple owns a piece of land (foreign) jointly worth $100,000 with a cost basis of $10,000, and parent A dies. Then the revised cost basis becomes $55,000 (1/2 is stepped up to $50,000 plus the surviving parents $5,000 basis). Assuming the 3 children receive the deceased parents interest, their combined basis is $50,000. Thus, the beneificaries will only pay tax on the appreciation since the date of death of the inherited property.
If the deceased parent owned 100% of the property, then the cost basis to the beneficiaries is 100% of the FMV as of the date of death. Also, the tax law assumes that the holding period is automatically long-term regardless of the actual term the deceased held it. Thus your sale will be considered long-term and will receive favorable long-term cap gain rates.
U.S. estate tax law is that an estate tax return (Form 706) will only need to be filed if the gross value of all the decedents assets (before considering mortgages or liabilities) exceeds $1,500,000 (for deaths in 2004 and 2005).