A few days ago, Sam posted about compiling Flex 2 and AS3 via Ant in PrimalScript. Well, his setup is now an official part of PrimalScript 4.0! Can’t say those boys at Sapien don’t respond to customer requests.
Here’s how it works:
Here’s a glimpse of the build.xml file it creates. You are free to customize this however you want, adding additional parameters, etc.

You’ll need to have Apache Ant set up and the Ant folder should be in your path. More info on how to set that up here. You can then set up PS to execute Ant when you hit F7, keying it to the ActionScript and/or Flex file types. Set it up like so in Options:
You are also free to have it open up in the standalone player if you want. Just change the player variable at the start of the build file to contain the path to the player. Alternately, you could have the html file launch.
Of course, this set up isn’t 100% workable for large projects, as there is still no code hinting, etc. But that will be along shortly. Still, it’s a first step and very exciting. And as soon as the free Flex 2 beta is no longer beta, and no longer free, this will be pretty useful for anyone who wants to work with the free command line compiler without paying for Flex Builder 2.