First you need is ssLauncher. You can get the free versoin from here:
Or payed version from here:
If you've installed ssLauncher you can make your own theme and post it here. Or you can download a theme from here and open it up with ssLauncher.
Loading a theme:
Copy the downloaded .zip file to the root of your SD-Card. Then push the settings button on your phone and go to "more" settings. After that select "load" and choose the .zip file on your SD-Card.
Saving a theme:
First of all you must save your template by longer pressing a free place on your display. A menu appears with several options. Choose "save template". If you do this more than one time you must delete all useless templates befor you can proceed with the next step.
Next step is similar than "Loading a theme". But choose "save" and then your SD-Card to save your theme. Now you can find a zip. file on your card named like "ss_20120224_172531". Copy it to your PC and rename it if you like.