Hi, I would like to store about 500 zip codes in a custom object called rates that have corresponding zip codes.  Then I would like to look up those sales taxes by zip code in leads.  In Microsoft Access, this would be a breeze by simply linking the zip code between the two tables Rates table and Leads table for example.  I don't have any idea how to do this in salesforce.  If anyone can point me in the right direction I would appreciate it.  thank you!
 

I'm trying to run a custom report that focuses on a date field that currently has no value associated with it.  My ideal situation would be to be able to run a report where date equals <blank> but I can't seem to get that to work.  Any ideas?