The "Droid Factory" startes off as a Wal-Mart exclusive where you will be able to get 6 unique 2-Packs to build C-3PX. Those come out on July 1, 2008.

Then after that starting with Legacy Collection single carded figures each one will come with a part to build a unique never before release droid. Waves that come with 8 figures will allow you to build 2 astromech droids and waves with 6 figures will allow you to build 1 protocol droid.

The parts will have universal connectors for customization.

The first regular Protocol wave starts in the Legacy Wave 3. Wave 2 is due out on 8/2.