viewController.m

-(IBAction)show:(id)sender{
	CGRect frame = [aView frame];
	frame.origin.y = [[self view] bounds].size.height;
	[aView setFrame:frame];
	[[self view] addSubview:aView];
	
	[UIView beginAnimations:@"slide up" context:NULL];
	frame.origin.y = [[self view] bounds].size.height - frame.size.height;
	[aView setFrame:frame];
	[UIView commitAnimations];
}


-(IBAction)dismiss:(id)sender{
	CGRect frame = [aView frame];
	frame.origin.y = [[self view] bounds].size.height;

	[UIView beginAnimations:@"slide down" context:NULL];
	[UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];
	[UIView setAnimationDelegate:self];
	[aView setFrame:frame];
	 [UIView commitAnimations];
}

-(void)animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context{
	[aView removeFromSuperview];
}