The weird thing is, after I wrote a 1,000 word outline for that, I realized I didn't like the ending. I liked the sci-fi part of it though, so I've changed the setting (now mid 1950s), come up with completely different set of characters, changed the non sci-fi part of the plot and did a lot of online research. This morning, I took another look at it and changed the beginning one last time. So far, I'm up to 700 words. I expect to finish the first (3,500-word) draft by the weekend.
I'm a great believer in using outlines (I even do one for the 100-word drabbles I write). I find it enormously helpful to get the whole story straight in my head before I start to do the first draft. Even though I've spent a lot of time and effort on the above-mentioned sci-fi idea before putting pen to paper as it were, and despite the fact that I may well change some other things as I go along, I consider it more than worthwhile, since (at least as far as I'm concerned), I've ended up with a stronger story than the one I'd have told if I just sat down and started typing.
How about you? Does anyone else outline short stories?