Yesterday Sun finally released OpenSolaris. OpenSolaris is simply the x86 version of Solaris 10 made open source. Making the OS open source should increase Solaris' share on the market because with more people working on it more hard/software can be supported and more people will use it. Releasing the code also gives other developers the opertunity to learn from Solaris' code, which contains some advantages like good SMP support. Not all code is released as of yet, though this will be done soon. More information (and the source) can be found here.