Google has just released the source code for Android Wear into the AOSP tree, so if you were waiting to get your hands on it to work with it you now have the capability. There are only some minor changes here so nothing worth getting too excited over, but eventually we'll see more from Google in this regard as they also stated that they plan to do a full platform push with the next Android Milestone. That will most likely be Android L which will be releasing later this year in the fall, so we could see specific source code for the Gear Live, and the G Watch, and possibly any other Android Wear devices that might release in that time be made available once L is pushed out to devices.
This small number of GPL projects for the Android Wear source code can be found under the android-4.4w_r1 tag, and the kernel source is kernel/msm with branches android-msm-sprat-3.10-kitkat-wear and android-msm-dory-3.10-kitkat-wear. It's not a whole lot to work with right now, but we're not far off from the release of Android L, most likely only a few more months, and when that time comes we should see a whole lot more Android Wear source code made open and available to the public.
That should open up some awesome possibilities for crafty developers to work their magic and bring some interesting stuff to the Android Wear platform, although we're already seeing some interesting stuff hit the Play Store in the form of Android Wear compatible apps. Android Wear is still fresh of course but apps for the platform seem to be coming along nicely and more seem to be added on a daily basis. Android Wear may only be just about a month old in terms of device release, but it's coming along quite quickly and we should really start to see it take shape as more Android Wear smartwatches and devices come to market. As more devices are launched, more developers might be inclined to get their hands on them and we should end up seeing even more awesome Android Wear development.