I'm thinking I could log into iTunes with my US account, download the app and then sync it to my iPhone.
Only thing I don't know is if it would just come up with US listings or something like that?
If the app in question only supports US listing currently, then yes, only US listings will be shown.
However, if the app supports UK listings alongside US listings, it will show UK listings.
Buying the application on a US account and syncing to a UK iPhone has no affect (in any way) on the standard,
built in, region support of the application.
R-Fly