Fleeting Ghost is a level 2 at-will utility power that allows you to make a Stealth check. But I would read it to allow you to sneak around at your normal move speed; I wouldn't read it to do away with the normal prerequisites for going into hiding.
Chameleon and Shadow Stride, level 6/10 at-will utility powers, requires you to be hiding (successfully so, I assume) to start with.
At level 16 there is an encounter utility that you'd think do the job, based on its name: Hide in Plain Sight. However, it too requires you to be hidden.
Again at level 22: You must already be hidden (Hide from the Light).
Every rogue level has an at-will utility that facilitates this.
It's not difficult.
Do you mean "every rogue utility level"?
Assuming you do, I can't find them in the PHB; which pretty much means I disagree with the "not difficult" part (if you need a splatbook to do it, a lot of rogues won't ever be able to do it).
Remember, KarinsDad is asking about powers that work right out in the open, when you have no cover or concealment available.
If you are hiding already, you've already done the hard part. Just maintaining stealth is relatively easy; acquiring it in the first place - in, say, a brightly lit empty parking lot - is not as easy (not by my reading of the PHB utilities, at least)