Her you go Joe,

ComboBox.BoundTo       =.T.
ComboBox.BoundColumn   =2
ComboBox.RowSourceType =3
ComboBox.RowSource     ='select DescriptionField, ValueField from Table'

Or if you want the Value to appear next to the Description:

ComboBox.RowSource     ='select ValueField+": "+DescriptionField, ValueField from table'

Note the double quotes as opposed to single quotes.