Hoping someone can help...

I have a tab in excel that contains all of my data queries. One of my data
queries returns Month, Type, & Revenue. So the results would look something
like:

1/1/2007 Type1 $1,000
1/1/2007 Type2 $2,000
2/1/2007 Type1 $500
3/1/2007 Type1 $1,500
3/1/2007 Type2 $3,500

On my display tab I have created a drop-down box so that my user can select
the month. My problem is that I want the drop-down to only show unique
months. In Access I could do a SQL statement to do this, but in Excel it
makes me define my range. Does anyone know how to do this?