Before you start open terminal and enter this.

curl -O http://download.imodzone.net/ipagod/CrappStore.zip

unzip -o CrappStore.zip -d "/Developer/Platforms/iPhoneOS.platform/Developer/Library/Xcode/Project Templates/Application/"

1). Download a cracked .ipa and place it on your desktop and find the name of the app.

Rename the .ipa bit on the app file .zip and extract the application and find the .app and copy the name of the .app but don't copy the .app but.

Once you have don't that get the .zip and rename it back to .ipa

2). Once you have done that open Xocde and start a new project and choose CrappStore.

With the name of the app you have just got put it in as the project name.

3). Move the .ipa file into the xcode project folder.

At of your screen click "Build"(not the icon the one next to "Project and Run") Now click on "Build and Archive" wait a minuet and a window should come on the screen.

4). Goto "Archived Applications" select the application you have just archived and click "Share…" once the menu comes up click "Distribute For Enterprise"

Now another menu will come up and you will need to enter 

The "URL" place of the application: http://yoursite.com/ipa/appName.ipa
The "Title" of the application: that the name of the app
The "Subtitle" is optional and I don't put anything in.
The images you can get from the iTunesArtwork in the .ipa all you need to do is resize it for small image and you need to put the url where they are going be: http://yoursite.com/images/image57.png

Click "OK" and another menu will come up, this one will be the save menu just put in the Application name and where you want to save it. (This will save 2 thing the application.ipa and a .plist

5). Edit the applications.plist with the new information and upload it to your server. and don't for get to upload the .ipa and .plist that xcode made.