I'm not sure what you mean regarding compression, but you can normally just change the dimensions that are specified for the Flash movie in the html code used to embed it in the web page. If it includes imported images, their quality may suffer a bit, but otherwise, Flash created content (graphics/text) will resize cleanly. This means no change is needed for the Flash file itself, just the html page code.
Beyiond that, there is no quick and dirty way to physically resize the original file dimensions within Flash, especially if it involves alot of timeline content.
I think that was the answer I was afraid of. I was wanting to shrink the size of the file. The current dimensions of the .SWF are 423 by 377 and the file size of the swf is 198 kb. I probably want to change height to about 120 pixels. If I just resize with html, I assume the file will still be 198 kb. So that probably doesn't help the download speed. The swf I am refering to is at htpp://www.thelibrarydoor.com. I assume this is probably too time consuming to go back and try to redo the movie (given I haven't messed with flash too much in years).
you can right click on the stage and click document properties to change the dimensions, but due to vector format this won't actually decrease file size.