customize the text of navigationbar

UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 320, 30)];
label.font = [UIFont boldSystemFontOfSize:14.0];
label.shadowColor = [UIColor colorWithWhite:0.0 alpha:0.5];
label.backgroundColor = [UIColor clearColor];
label.textAlignment = UITextAlignmentCenter;
label.textColor = [UIColor whiteColor];
self.navigationItem.titleView = label;
label.text = [dataItem objectForKey:@"title"];
[label release];

Creating a left-arrow button (like UINavigationBar's “back” style) on a UIToolbar

// create button
UIButton* backButton = [UIButton buttonWithType:101]; // left-pointing shape!
[backButton addTarget:self action:@selector(backAction) forControlEvents:UIControlEventTouchUpInside];
[backButton setTitle:@"Back" forState:UIControlStateNormal];
// create button item -- possible because UIButton subclasses UIView!
UIBarButtonItem* backItem = [[UIBarButtonItem alloc] initWithCustomView:backButton];
// add to toolbar, or to a navbar (you should only have one of these!)
[toolbar setItems:[NSArray arrayWithObject:backItem]];
navItem.leftBarButtonItem = backItem;