Run application with other user

[kellyremo]

OS: Fedora 14
GUI: GNOME

I need to run an application with another user then the "default" (normally
used).
Purpose: create a ".desktop" file on my desktop to run e.g.: Google Chrome with
another user (NOT ROOT! - so beesu doesn't count.)
There aren't any gksu, or kdesu packages in Fedora 14. Why?

So i want to create a user with "adduser SOMEONE", and i want to run e.g.:
Google Chrome with "SOMEONE" - then it will have minimum permissions, "more
security".

Thank you!