Who exactly is your comment "I am asking you to fix this problem soon" directed at?
Remember that you are posting on a user to user forum so nobody can really help you. If you want to give feedback to Apple, then contact them directly at http://www.apple.com/feedback.
Also, if you have an iPhone 3G and iOS 4.2.1 is the latest software that you can install on your phone, then there is absolutely nothing that anyone can do to fix the problem if you want to install Skype that requires iOS 4.3 - what do you think anyone can magically do?
iPhone 3G is a very old phone now and if you want to install Skype on your phone, then you need to go out and buy a new iPhone - either a 4s or a 5. Nothing more to it. Buy a new phone.
The iPhone 3G came out nearly five years ago. The highest version of iOS it will support is 4.2.1.
There have been four generations of iPhone released since the 3G. Any of those four could run iOS 4.3 or greater.
Why do people only target Apple?
As Courcoul said, windows 95 wouldnt run Skype, but i'm sure nobody is over their forums whinging about an issue that is only present because people are too cheap or stingy to actually upgrade their phones
If you support Apple so much, why not get a phone thats not ancient?
And on a technical level, the issue isn't that apple doesn't support it, its that the App Developer has only made the app available for 4.3 and up.