Calculate number of weeks between two cells

[Jane Schuster]

How do I calculate the number of weeks between two cells?
Example

B2 = 1/1/08
B3 = 5/10/09
B4 = Formula for # of weeks between B2 and B3

Any assistance would be greatly appreciated.

 

[Tim Zych]

One interpretation:

=INT((B3-B2)/7)