An incremental Android update adds APIs for writing tags as well as reading them.
The update also adds a notification system for interested applications, but no access to the secure elements just yet.
Android version 2.3, Gingerbread, brought the ability to read NFC tags and some hidden APIs to write them. With version 2.3.3 those hidden APIs are outed, and applications can be launched by reading specific tags, while those running in the foreground are able to intercept and process tag reading events before that happens.
The latter will be useful for the more esoteric applications of Near Field Communications (NFC), such as setting up DLNA connections or Bluetooth pairing, but for the payment systems that are attracting the most interest Google will need to provide standard APIs for accessing the secure element(s), and managing the applications housed therein.
But for fun stuff the Gingerbread NFC APIs are coming together nicely, which is good as we expect to see a lot more devices making use of them in the next few months. ®
* The British education system was set up to teach the three R's - reading, wrighting (making stuff, as in wheelwright) and reckoning (working stuff out). The changes in spelling and meaning often confuse those who only remember the original intention.