VS Upright 1 is a free VST/AU instrument plug-in for Windows and Mac.
Designed as a light-weight sketching piano, theVS Upright No. 1 is a clean sampling of an upright piano, the standard of homes, small clubs and studios around the world. With a broad dynamic range and a bright, clear tone, the upright can still display a soft side when needed.
Keolab has announced that its Spicy Guitar acoustic guitar synthesizer plug-in is now available for Mac OS X in 32/64-bits universal binary (VST/AU) and for Windows in 64-bits (VST).
Archetype Instruments has launched Lokomotiv, a free retro style synthesizer instrument.
Lokomotiv is designed to make your sounds more powerful and create wide range of sounds way easier. It supports both Mac and Windows with native 64 bit processing.