i just checked their website and it says he'll be there tomorrow (Tuesday):
News & Events
E-40 In-store CD Signing - 3/14/2006 04:00 PM
Tower Emeryville (5703 Christie Ave, Emeryville, CA )
The "Ambassador of the Bay," E-40, is leading the Hyphy Movement nationwide! Meet E-40 at Tower Records Emeryville for an exclusive street date CD signing of his highly-anticipated, new album, My Ghetto Report Card. E-40 is leading Please note: Starting 10am on Tuesday, March 14th, purchase your copy of "My Ghetto Report Card" at Tower Records Emeryville and get a priority wristband to meet E-40 in person. Wristbands are limited. One wristband per customer per CD purchase. Event subject to change. Please call store for details.
http://www.towerrecords.com/Stores/store.asp?storeID=t17120