1) Download the software called Kuaiyong
2) Launch the setup of Kuaiyong, and install it (simple setup)
3) After Installing the Software, plug-in your iDevice with USB Cable.
4) Now Launch Kuaiyong application from Desktop, it will look like below:
5) It will show a list of Apps and Games (Paid), you can search using the Search Bar or you can select an app from the list.
a) Search Bar
b) List navigation
6) After choosing an App or Game to download, Click on it then Click the Red button like below.
7) It will starts downloading the app. Just wait until it completes Downloading.
8) After it downloads the Paid app wait some time to Sync the App and add it to your iPhone, iPad or iPod...
Note#1: This works on all iDevices including: iPhone 3G, iPhone 3GS, iPhone 4, iPhone 4S, iPhone 5