Hmm... 10.2.3 is not very important. They'll fix some bugs in the system and some applications, they'll add support for some new CD-burners to the Finder, Disk Copy and iTunes. It'll appear in Software Update. Don't expect it this week, though. There's going to be a beta seed phase of about three or four weeks. We might see it in mid December.
10.3 will surely be much more interesting. I'm already looking forward to installing an early build on my external harddisk, but alas, there are none as of yet.