You can get the ISE 10.1 software free from the Xilinx web site. The current version is 11, but a link in the upper right hand of the Downloads Entitlement Page reads "Looking to register 10.1 or earlier software products?"
If you click that, you can download ISE WebPACK 10.1 as a free download.
This, as best I can tell, supports the Virtex II. The current version of the ISE picks up at Virtex IV.
Here's a document from Xilinx that might be helpful in finding documentation about ISE 10.1.
Notice that you can do simulations with this software.
More soon,-Michelle W5NYV