It's Flex'O Mania

Use the standard page viewer web part of the SharePoint Portal Server.Many organizations use SharePoint Portal Server widely as a portal or website. If you want to plug in your standalone Flex 3 application inside SharePoint Portal Server, follow these steps:
1 .Compile your Flex 3 application using Flex Builder 3 and run it. This will create a .swf file to be embedded inside your SharePoint Portal Server. You can get this swf file inside the ‘bin’ folder of your Flex project.
2. Log in to your SharePoint Portal Server; make sure you have the rights to edit the site or page of this portal. Upload this compiled .swf file into a document library of your portal.
3. Add a web part named “Page viewer web part” to your page. In the link property, specify the URL of the uploaded swf file. You can get this link by clicking the file from the document library.

Your Flex application should now be running inside your SharePoint Portal Server.