To install a cab file: there are a couple of ways to do this below is the easiest method
On your PC

1. Hook your phone to your pc
2. ActiveSync will open on your desktop
3. Click Explore.
4. Copy the cab file to \Windows\Start Menu on your device

On your Device/Phone

1. Press Start.
2. Scroll down till you find your cab file on the list.
3. Open the .CAB file.
4. The application will install on your device.

Remember to say yes or ok to everything it says, it will give you a warning telling you that this program may display incorrectly due to it being designed for an older version of windows. This is just something in the cab file and has nothing to do with the actual home screen and will not affect the way the home screen displays.After installation is complete go to your home screen settings and select the home screen you just installed.

To install a rar or a zip file:
To install a rar or a zip file you will first need to unzip or unrar the file. A rar file is just like a zip but uses a different form of compression. Please google winrar you can download it for free.
Enter your search terms Submit search form Next after obtaining winrar unzip your rar or zip file. It should unzip to either have a folder and an something.home.xml or a jpg file or 2 and a something.home.xml after you have the files extracted copy the files over to your application data/home folder.If you are not sure hoe to do this follow these steps
On your pc:

1. Hook your phone to your pc
2. ActiveSync will open on your desktop
3. Click Explore.
4. Navigate to \Application Data\Home and copy the files there

After installation is complete go to your home screen settings and select the home screen you just installed.

Trouble Shooting
If you are seeing a bar at the top of the screen and the text is not aligning properly to where it should be there could be 1 of 2 problems.

Problem 1: In your home screen settings you do not have your background set to default. If you set this to anything else it will change how the wallpaper sits behind the plugins and screw up the alignment. To fix this set the background image to default.

Problem 2: In your home screen settings you do not have your color scheme set to default or to a color scheme that does not have a background image as part as the scheme (note the color schemes that come standard with the phones all have wallpapers associated with them. If you choose one of these it will change the background). To fix this set the color scheme to default or if you wish to change the color scheme go to my color schemes page located here and download either my Black Soft Keys color scheme or one of my other softkey color sets.

Thanks to eko who wrote this handy tutorial and who also makes great home screen, click here to visit her web site.