Yes, just follow these steps:

1. Launch Intellisync for Yahoo!.
2. Click "Setup."
3. Click "Application Settings."
4. Choose "Calendar."
5. Click the "Advanced" button.
6. On the next page, customize the date range.

You can further customize your synchronizations by changing your preferences in the "Confirmation" tab, the "Conflict Resolution" tab, and the "Field Mapping" button. Make sure to select "OK" after making any changes.