Until Flex Builder 3 Stand Alone includes Ant built in you will have to install it separately. Peter Elst wrote steps for installing it in Flex Builder 2 but in Flex Builder 3 the steps are slightly different. For those that are not familiar with Eclipse, this can be tricky to install.
The following is the revised steps for Flex Builder 3 Stand Alone.
Quoted and revised from http://www.peterelst.com/blog/2006/09/03/flex-builder-2-ant-support/:
Launch Flex Builder 3 Go to Help > Software Updates > Find and Install Select “Search for new features to install” and click next Select “The Eclipse Project Updates” and click finish
Note: If you do not have the option above click New Remote Site and enter "The Eclipse Project Updates" as the name and "http://update.eclipse.org/updates/3.3" as the url. Accept the license agreement and click next Click finish to start download Eclipse downloads Java Development Tools Click “Install all” to install Java Development Tools Restart the Eclipse workbench
That’s it! You now have Apache Ant support in your standalone Flex Builder 3 install.
Go to Window > Other View > Ant and Click OK. You now have the Ant view

Please vote for ANT to be included in future versions.
Hmmm…interesting…

Thanks, that was a useful addendum. Much appreciated!
Java Development Tools does not show up for me. It seems that the latest beta already includes the necessary Ant files.
The problem is that there are no menu items, etc. like in normal Eclipse for creating Ant tasks, etc., and not Ant section in the Preferences.
Any idea how to get those to appear?
@Ken
Yes Flex Builder 3 Beta 3 includes Flex Ant Tasks in the SDK folder, but you can’t use them until Ant has been added to Flex Builder. The steps above correct this through the installation of the Java Development Tools.
If you go to Menu: Window > Other views…
and the resulting ‘Show View’ dialogue doesn’t include an Ant view – then you do not yet have ant properly installed. You need to try again and go carefully through the steps above.
Ken,
You can also look for Java Development Tools under Europa Discovery Site.
Matt
Priceless! Thanks for pointing me in the right direction for Ant integration in Flex Builder 3. I’m looking into exporting Ant build scripts from the IDE.
[...] http://www.judahfrangipane.com/blog/?p=193 [...]
In my case, I had to select “Filter features included in other features on the list” on the search results before JDT showed up.
Thanks Sam! If you think these should be included in the standalone go here,
http://bugs.adobe.com/jira/browse/FB-10857
yeap! thanks a lot! nice tutorial
Thanks Dude, that’s helped me a lot :D
Note: The site url provided for installing the JDT is no longer available. (At least my team and I could no longer install it from the above location).
However, a mirror is still up here:
http://d2u376ub0heus3.cloudfront.net/releases/europa/site.xml