Temporarily set your home location as one cache, and see the distance to the other cache at the top, there might be a better way of doing this but not that I've heard of.
You wiil need to re-grab the trackable, and edit your find log on the cache you want to place it in with a dropped log which is under where you type your log.
Just wondering how many of you find a tb, place it, then find it again in another cache again! This happend to me today with http://www.geocaching.com/track/details.aspx?guid=b39100c7-7604-4685-a907-fa9c8b9b4bb9