I would like to let my friends tweet using my Twitter handle but I want to be able to moderate their tweets before they go out. Is there any way to do this?
You can’t do it through the Twitter apps (to my knowledge, at least), but you could (potentially—I haven’t used it) the third-party client Birdhouse.
Capture your ideas, refine them later, publish when ready
Ever think of something for your Twitter that you don't want to post right away? Birdhouse is the perfect place to put it.