How to change the Color of text in UITabBarItem in iOS 5

Do you mean this one? Keep in mind, this only works for iOS5.0 or later.

if ([self.tabBarItem respondsToSelector:@selector(setTitleTextAttributes:)]) {    NSLog(@"*** Support method(iOS 5): setTitleTextAttributes:");    [self.tabBarItem setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:                                                [UIFont fontWithName:@"AmericanTypewriter" size:20.0f], UITextAttributeFont,                                                [UIColor blackColor], UITextAttributeTextColor,                                                [UIColor grayColor], UITextAttributeTextShadowColor,                                                [NSValue valueWithUIOffset:UIOffsetMake(0.0f, 1.0f)], UITextAttributeTextShadowOffset,                                                nil]];}

Apple's documentation on customizing appearance:

In iOS v5.0 and later, you can customize the appearance of tab bars by setting item label text attributes using appearance selectors declared by UIBarItem. You can also use the methods listed in “Customizing Appearance.” You can customize the appearance of all segmented controls using the appearance proxy (for example, [UITabBarItem appearance]), or just of a single tab bar. You can also provide finished selected and unselected images using the methods listed in “Managing the Finished Selected Image”; these methods, though, do not participate in the UIAppearance proxy API (see UIAppearance). UIKit does now provide any automatic treatment to finished images. For good results, you must provide finished selected and unselected images in matching pairs using setFinishedSelectedImage:withFinishedUnselectedImage:.

Edit:Here is another example using the UIAppearance system and the NSDictionary literal syntax:

[[UITabBarItem appearance] setTitleTextAttributes:@{                         UITextAttributeFont : [UIFont fontWithName:@"AmericanTypewriter" size:20.0f],                    UITextAttributeTextColor : [UIColor blackColor],              UITextAttributeTextShadowColor : [UIColor grayColor],             UITextAttributeTextShadowOffset : [NSValue valueWithUIOffset:UIOffsetMake(0.0f, 1.0f)]}];

Edit (by @JeremyWiebe): As of iOS 6, the dictionary keys have been changed to be the same as OS X uses:

NSShadow *shadow = [[NSShadow alloc] init];shadow.shadowColor = [UIColor grayColor];shadow.shadowOffset = CGSizeMake(0, 1.0);[[UITabBarItem appearance] setTitleTextAttributes:@{                         NSFontAttributeName : [UIFont fontWithName:@"AmericanTypewriter" size:20.0f],              NSForegroundColorAttributeName : [UIColor blackColor],                       NSShadowAttributeName : shadow }];

[[UITabBarItem appearance] setTitleTextAttributes:@{                             UITextAttributeFont : [UIFont fontWithName:@"HelveticaNeue-Bold" size:10.0f],                        UITextAttributeTextColor : [UIColor colorWithRed:0/255.0 green:48/255.0 blue:92/255.0 alpha:1.0],}                                         forState:UIControlStateNormal];[[UITabBarItem appearance] setTitleTextAttributes:@{                             UITextAttributeFont : [UIFont fontWithName:@"HelveticaNeue-Bold" size:10.0f],                        UITextAttributeTextColor : [UIColor colorWithRed:0/255.0 green:138/255.0 blue:196/255.0 alpha:1.0],}                                         forState:UIControlStateSelected];

UITextAttributeFont, UITextAttributeTextColor etc. are deprecated in iOS 7.0.

You have to use:

NSFontAttributeName, NSParagraphStyleAttributeName, NSForegroundColorAttributeName, NSBackgroundColorAttributeName, NSLigatureAttributeName, NSKernAttributeName, NSStrikethroughStyleAttributeName, NSUnderlineStyleAttributeName, NSStrokeColorAttributeName,  NSStrokeWidthAttributeName, NSShadowAttributeName and NSVerticalGlyphFormAttributeName