//declare this in the .h file
InfoPopoverController *popoverContent;
UIPopoverController *popover;


-(IBAction) infoButtonClicked:(id)sender{
	popoverContent=[[InfoPopoverController alloc] initWithNibName:@"InfoPopoverController" bundle:nil];
	popover = [[UIPopoverController alloc] initWithContentViewController:popoverContent];
	[popover setDelegate:self];
	[popover setPopoverContentSize:CGSizeMake(989,545)];
	popoverContent.contentSizeForViewInPopover=popoverContent.view.bounds.size;
	[popover presentPopoverFromRect:((UIView *)sender).frame inView:self.view permittedArrowDirections:UIPopoverArrowDirectionDown animated:YES];
}

- (void)popoverControllerDidDismissPopover:(UIPopoverController*)popoverController{
	if (popover) {
		[popover dismissPopoverAnimated:YES];
		[popover release];
		popover=nil;
		if (popoverContent != nil) {
			[popoverContent release];
			popoverContent = nil;
		}
	}
}
-(void)killPopoversOnSight {
	if (popover) {
		[popover dismissPopoverAnimated:NO];
	}
}

Display a UIPopoverController

Objective C