Yeah, it sounds like you're after VB select case functionality. There is an access query equivalent that you can use directly in the query. You might want to try the Switch function. Here is an example that translates one character codes in a database field into "english" words for display on a report:
[tt]
SELECT Switch(Method='P','Percent',
Method='F','Flat Rate',
Method='A','Additional Amount',
True,'Unrecognized Code') AS EnglishMethod
FROM ExampleTable
[/tt]