The first time home buyer credit applies for up to 10% of the purchase price of the home, not to exceed a maximum of $8,000. The $4,000 mentioned in the update applies only when married couples are filing separate returns. Each filer is allowed up to a $4,000 credit. A single individual qualifies for the maximum, up to the full $8,000.  This same approach is used for the newly introduced home owner tax credit that allows people who have owned their home for five consecutive years. The difference is the maximum credit is limited to $6,500 or $3,250 for married filers filing separately.  The IRS issued Notice 2009-12 earlier in 2009 to provide guidance for allocating the credit between unmarried purchasers. The extension will not affect the allocation methods described in the IRS notice. You can access a copy of that IRS notice at by going to www.immaag.com. This chart below can be a helpful resource as you take advantage of the credit in the months ahead.
http://www.realtor.org/fedistrk.nsf/files/government_affairs_tax_credit_ext_chart_110409.pdf/$FILE/government_affairs_tax_credit_ext_chart_110409.pdf