http://www.opencores.org/projects/or1k/Silicon

“The LEON2 processor is a synthesisable VHDL model of a 32-bit processor compliant with the SPARC V8 acrhitecture. The model is highly configurable, and particularly suitable for system-on-a-chip (SOC) designs. The full source code is available under the GNU LGPL license, allowing free and unlimited use in both research and commercial applications.” http://www.gaisler.com/leonmain.html

MIT has released an HD quality H.264 baseline profile decoder, an OFDM transceiver and an 802.11a WiFi transmitter » http://csg.csail.mit.edu.nyud.net/oshd/index.html