So besides patronizing businesses that were vandalized in general, you can support them and celebrate Oakland at the same time. Oakland merchants are sponsoring Celebrate 17th on 17th Street tomorrow from 2pm to 5pm. That's in addition to tonight's Night Out event. There's a nice writeup on it over at The DTO.
P.S. From the worth reading department: city councilmember Pat Kernighan's thoughts on the killing of Oscar Grant and the aftermath.