STEP 1:

Create a new account on your PS3

STEP 2:
Visit the Sony Play Station Store and set your country to United States / United Kingdom, depending on the channels you want to download.

STEP 3:
Exist the PlayStation Store and go to TV/Video Service -> My Channels.
You should now see the apps available for download, depending on US / UK account.

STEP 4:
Switch back to your old PS3 account to run the apps.