You shouldn't just wait till you get your second package. The first numbers for DV-2009 will be published in the advanced notification section of the September bulletin (this bulletin will come out around the 15th of August). If your number is below the one listed for EU, you can wait a few days and then call or email KCC to ask about your interview date. The reason why you should do that: sometimes the second package arrives late or not at all so you have to make sure you know when your interview is.
In case you didn't know yet about the visa bulletin, here's the link:
http://www.travel.state.gov/visa/frvi/bulletin/bulletin_1770.html
I agree with Tazmania: Most likely you will have your interview in October (which is the first month for DV2009). So you better get your documents ready.