This page provides help for using the fpga_analyzer from Synopsys.
Student Contributed Documentation
Graphical instructions tutorial on how to map your VHDL code to the Xilinx chip using fpga_analyzer.(EMo)
Similar information on fpga_analyzer but including steps on how to write your code to the Xilinx chip and how to use the Rapid-Prototyping Board (RPB-demo). Check out the code they used to do it all.(Ray and Shazia)
These guys thought they were so smart switching from Actel to Xilinx. Guess again. Here are a few tips they learned along the way. (They did get a working demo on Xilinx) (Quentin and Aaron)
Other Documentation
If you can not get rid of all your errors and warnings, or if your code is just too darn big check out the manual put out by Xilinx which provides a general overview of designing FPGA's using VHDL.
The Xilinx home page may be of help if you can't find anything here.