I ordinarily use a formula like this, where {?FiscalYear} is a number parameter, for a record selection formula:
{table.date} in date({?FiscalYear}-1,7,1) to date({?FiscalYear},6,30)
If you are trying to group your date fields based on fiscal year or use it in charts or crosstabs, you can use a formula like this:
"FY "+totext(year({table.date}+184),"0000")
-LB