Jeremy Wariner's summer schedule is posted on his website. He plans on running 5 races in Europe between July 10th and 8/07/07 leading up to the IAAF World Championships in Osaka, Japan, which will be held between August 25th and September 2nd.
Wariner hasn't listed, like he usually does, which events he'll be running. We can assume that he will be running mostly 400m races with maybe a 200m or two thrown in for speed-tuning purposes. A check of the meet websites doesn't reveal much about which events he will be running, although we do know that he will be racing Oscar Pistorius in the 400m in Sheffield. No 400m Dash is scheduled for the Vardinoyiannia in Greece, so we can assume Wariner will run the 200m there. Wariner is listed in the 200m start list of the Athletissima website. Finally, we can assume Wariner will run the 400m in Galan because he has run the 400m there both in 2005 and 2006, winning both times. As for what event he will run in London, we can only speculate, but that meet will be so close to the world championships that running a 400m race would make sense.
7/10/07: Athletissima (Lausanne, Switzerland) 200m
7/15/07: Norwich Union British Grand Prix (Sheffield, England) 400m
7/18/07: 23rd Vardinoyiannia (Réthimno, Greece) 200m?
8/03/07: Norwich Union Super Grand Prix (London, England) 400m?
8/07/07: DN Galan (Stockholm, Sweden) 400m?