Project Soul just announced during their panel at San Diego Comic-Con that they are planning to release Soulcalibur 2 HD Online. This game will feature all the modes from the original version, and will also include Heihachi Mishima from the PS2 version.
It's unknown if Link and Spawn will return, but hopefully they will make their way in. And, much like the name suggests, it will include full online functionality.
Soulcalibur 2 HD Online is set to release this fall for PlayStation 3 and Xbox 360.