Well, that was fast. Android 4.1.2 was just released to AOSP last week, and Motorola has already started pushing the Wi-Fi XOOM's update out to soak testers. This isn't a huge jump in terms of functionality, and the incremental update will bump the XOOM from build JRO03H (4.1.1) to JZO54K (4.1.2).
Of course, those who aren't soak testers are probably wondering how they can get this update now. The beauty of Google-supported hardware like the Wi-FI XOOM (which is, for all intents and purposes a Nexus device), is that Big G makes updates likes this one available almost immediately. Therefore, it can be downloaded and manually applied right now.