Uniue Values from 2 colums - Formula

I am trying to determine the amount of days an employee has been at work. The employee's name & date can occur multiple times in the list of data. I would imagine you would need to find the unique number of occurences from a concatination between the 2 but that's not working for me.
I would really appreciate it if i could use the formula for each employee...
that way i could just copy the formula and reference the person's name.

EG. Uniue days where employee name = "Rich Armstrong" (Answer should be 3)
Uniue days where employee name = "Luke Siedle" (Answer should be 2)

Here's the data...

Date Name
2011/04/01 Rich Armstrong
2011/04/01 Luke Siedle
2011/04/01 Rich Armstrong
2011/04/01 Rich Armstrong
2011/04/01 Rich Armstrong
2011/04/01 Rich Armstrong
2011/04/01 Luke Siedle
2011/04/01 Luke Siedle
2011/04/01 Luke Siedle
2011/04/01 Luke Siedle
2011/04/01 Luke Siedle
2011/04/04 Rich Armstrong
2011/04/04 Rich Armstrong
2011/04/04 Rich Armstrong
2011/04/04 Rich Armstrong
2011/04/04 Rich Armstrong
2011/04/04 Rich Armstrong
2011/04/04 Luke Siedle
2011/04/04 Luke Siedle
2011/04/04 Luke Siedle
2011/04/04 Luke Siedle
2011/04/05 Rich Armstrong
2011/04/05 Rich Armstrong
2011/04/05 Rich Armstrong