Update @ 2012-08-07: As mentioned by Siby, the approach in this article may cause memory leak. Please try to use singleton as shown in the following link.
The Objective-C Singleton

Like Java, i would like to add a Static Class such that i could call static variables and static methods in any where.

In Objective-C, you can create a static variable using a static modifier.

For static method which is also known as class method, you can use the + sign instead of the – sign when declaring the method.

I have created a Utility class as follow.
Utility.h

@interface Utility : NSObject
+ (int)getNumber;
+ (void)setNumber:(int)number;
@end

Utility.m

#import "Utility.h"

@implementation Utility

static int number = 1;

+ (int)getNumber {
  return number;
}

+ (void)setNumber:(int)newNumber {
  number = newNumber;
}

+ (id)alloc {
  [NSException raise:@"Cannot be instantiated!" format:@"Static class 'ClassName' cannot be instantiated!"];
  return nil;
}

@end

Now i would like to get and set this static variable when loading HelloView. so I need to modify the HelloViewController.m.
HelloController.m

#import "Utility.h"

@implementation HelloController
...
- (void)viewDidLoad {
	[super viewDidLoad];
	NSLog(@"number = %d", [Utility getNumber]);
	[Utility setNumber:3];
	NSLog(@"number = %d", [Utility getNumber]);
}
...
@end

Run the application and check the Debugger Console.

2010-04-09 17:27:18.864 HelloWorld[10860:20b] number = 1
2010-04-09 17:27:18.874 HelloWorld[10860:20b] number = 3

Done =)

Update @ 2011-08-25: Add (id)alloc in Utility.m to avoid the class being instantiated. Thanks Liam. =)