I feel like I'm fairly informed, but until recently I've never found a good way to workaround Flash file uploads through Apache authentication (usually for a development or staging environment). In the past few weeks, someone mentioned using the Limit Apache directive to only restrict GET requests, allowing POST requests to go through. A couple others mentioned using LimitExcept, but my server(s) must not be configured to allow LimitExcept in .htaccess, as it produced an Internal Service Error no matter how I used it. Limiting GET works perfectly and I haven't personally seen this mentioned on Forrst, so I wanted to share with any frustrated developers out there looking for the same fix. I hope it helps someone else.