Salesforce can accommodate an organization's unique fiscal year start month. Fiscal year is used to determine months included in quarterly and annual forecasts and reports.
The System Administrator can set or change the existing fiscal year start month by clicking on:
Setup | Administration Setup | Company Profile, then set values.
1) Fiscal Year Start Month
Choose the calendar month which your organization uses to begin each fiscal year
2) Fiscal Year is Based On
Use this field to determine the fiscal year number choosing either [The Starting Month] or [The Ending Month].
The number of each fiscal year can be determined by the calendar year of either the beginning or end of your fiscal year.
So for example if your fiscal year is Sept-August the fiscal year beginning Sept, 2008 will end Aug, 2009 (calendar months).
You can either have that be FY2008 (per calendar year of first month) or FY2009 (based on calendar year of ending month).
WARNING: User Quotas will be deleted whenever fiscal year is changed. You may want to run a Quota report prior to changing this since users or the Admin will have to manually renter the values.