• http://sdb.amazonaws.com/crossdomain.xml is not available. This means no direct calls from Flash clients in browsers are possible!
• Even if it would be possible some day, you would need to find a secure way to deliver your AWS key to the Flash client.
• Using a web proxy is a solution that would cause a lot of traffic on your server.

So using Amazons SimpleDB for browser based Flash applications makes not much sense to me.
It might be more useful for Flash applications running on local machines like Flash projectors or Adobe AIR applications but there is still a security problem with hiding your AWS key.

Anyway, I found two ActionScript libraries that might be useful:
http://code.google.com/p/actionscript-simpledb-library/
http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1365

And this thread in Amazons discussion forums:
http://developer.amazonwebservices.com/connect/thread.jspa?threadID=19698

• MAMP – Apache and MySQL Server
• Virtual Host X – Create up to 3 virtual host with the free version.
  In other words: This provides an easy to use GUI which enables you to forward an local URL like “http://myProject.local” to your workspace directory.

But one thing sucks: You have to set read/write access (in finder) for everyone. I wonder if that might cause system security problems?

And I strongly recommend to read this nice tutorial about setting up virtual hosts manually: http://www.sawmac.com/mamp/virtualhosts/