u-he unveils ACE (Any Cable Everywhere), a new software synth for both Windows and Mac OS X. Looks cool!
ETA: early December 2009
formats: VST on Windows, VST/AU/RTAS on MacOS X
system requirments Mac: Apple Macintosh Computer running MacOS X 10.4+ on a G4 processor or newer, Intel Core 2 Duo or better recommended
system requirments Win: VST2 compatible host software on a PC with SSE2 supporting processor, Intel Core 2 Duo or better recommended
number of presets and such: tba
Find other synths here.