Xilinx ISE (www.xilinx.com).

Modelsim (www.mentor.com)

Free Tools:

Notepad++  a free source code editor and Notepad replacement, which supports several programming including VHDL and ADA (notepad-plus.sourceforge.net/)

Xilinx ISE WebPACK(http://www.xilinx.com/ise/logic_design_prod/webpack.htm or www.xilinx.com)

Modelsim XE free edition (with Xilinx Web Pack)

Ada Home: The Web Site for Ada http://www.adahome.com/

GNAT is a free, high-quality, complete compiler for Ada95, integrated into the GCC compiler system (http://www.gnu.org/software/gnat/)