travelin_cat - 7:00 pm on Apr 18, 2012 (gmt 0)
When you are in your "Channel" in YouTube, click on "Captions". Run your cursor over the area that says "Uploaded Captions:" A popup will appear that says "Edit Track". After you click on the area indicated, you will have an option to Delete or Download.
Note: this must be your channel, You cannot edit someone else's caption