Sorting Dates in a value list

[rpoelking]

I've run across this scenario more than once and I hope someone has a solution.

I have a regular date field and then a calc field that produces just the MonthName and Year from the date field. If I specify the data type to be date then the data appears wrong. So I left it as text. But now I want to return a value list based on that calculation. When I do, the list is alphabetized by the MonthName.

How do I get the list of dates to show up in order in the value list?