Micron Technology - VHDL, Verilog, and IBIS models of Micron's memory products - http://www.micron.com/
The Hamburg VHDL Archive - We intend to provide a collection of free, i.e. public-domain or shareware, VHDL documentation, models, and tools. - http://tech-www.informatik.uni-hamburg.de/vhdl/vhdl.html
Digital Core Design - Synthesizable VHDL and Verilog HDL IP Cores. - http://www.dcd.pl