There are two new devices added to the FT256 availability: XC3S700A and XC3S1400A. The XC3S700A and XC3S1400A FT256 pin-out is not compatible with the pin-out for the other family members in the same package because more power and ground pins were added for the higher densities.
There are also two new devices offered in the VQ100 package: XC3S50A and XC3S200A.
Pin-outs are available online at:
http://www.xilinx.com/support/documentation/data_sheets/s3a_pin.zip Software support for all of these new device/package combinations is available beginning in the ISE 10.1 design tools.
For more information, see the Spartan-3A Data Sheet (DS529):
http://www.xilinx.com/support/documentation/data_sheets/ds529.pdf