I don't know exactly if you have asked this but if you only want to compare the date component of a NSDate you have to use NSCalendar and NSDateComponents to remove the time component.
Something like this should work as a category for NSDate:
- (NSComparisonResult)compareDateOnly:(NSDate *)otherDate {
NSUInteger dateFlags = NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit;
NSCalendar *gregorianCalendar = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
NSDateComponents *selfComponents = [gregorianCalendar components:dateFlags fromDate:self];
NSDate *selfDateOnly = [gregorianCalendar dateFromComponents:selfComponents];
NSDateComponents *otherCompents = [gregorianCalendar components:dateFlags fromDate:otherDate];
NSDate *otherDateOnly = [gregorianCalendar dateFromComponents:otherCompents];
return [selfDateOnly compare:otherDateOnly];
}