Yup. On the cache, scroll down to "Post a Log/Field Note", then select "Log Type" followed by "Found". You can then upload it as a field note, or a log to the site. You should probably fill in "Message" first or get ready for some irate cache owner's log deletion.
Note you will need to re-run your query to remove the cache from the list of nearby caches, and that'll only work if you actually logged it (Field note is not enough). Bit of a shortcoming of the iPhone app.
Thanks northernpenguin
You bring up some interesting points but I have a question.
Yes it would be nice to delete FOUND CACHES for the nearest search list in the future. But at this point I don't see that option either.