set the UISearchBar BackGroundColor and back image...

for (UIView *subview in searchBar.subviews) {

        if ([subview isKindOfClass:NSClassFromString(@"UISearchBarBackground")]) {

            UIView *bg = [[UIView alloc] initWithFrame:subview.frame];

            bg.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"SkyBackground.jpeg"]];

            [searchBar insertSubview:bg aboveSubview:subview];

            [subview removeFromSuperview];

            break;

        }

    }

//And for change the background of TextField of searchBar see bellow code..

UITextField *searchField;

    NSUInteger numViews = [searchBar.subviews count];

    for(int i = 0; i < numViews; i++) {

        if([[searchBar.subviews objectAtIndex:i] isKindOfClass:[UITextField class]]) { //conform?

            searchField = [searchBar.subviews objectAtIndex:i];

        }

    }

    if(!(searchField == nil)) {

        searchField.textColor = [UIColor whiteColor];

        [searchField setBackground: [UIImage imageNamed:@"searchbox.png"]];

        [searchField setBorderStyle:UITextBorderStyleNone];

    }

For change the icon of searchbaricon

UIImageView *searchIcon = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"yourSearchBarIconImage"]];
searchIcon.frame = CGRectMake(10, 10, 24, 24);
[searchBar addSubview:searchIcon];
[searchIcon release];

and for set color 

[searchBar setTintColor:[UIColor colorWithRed:.81 green:.14 blue:.19 alpha:1]];//set alpha with your requirement

See My Answer for UISearchBar http://stackoverflow.com/questions/13817330/how-to-change-inside-background-color-of-uisearchbar-component-on-ios/13817915#13817915