I using ANT + SVN tasks a lot for compiling the startup for projects. Took me a while to setup it to work on MAC but the solutions was pretty easy. This will work on a PC as well.

What you first need.
You need the ANT plug-in and you can get that from Eclipse JDT Development
1.) Open Flex Builder
2.) Help -> Software Updates -> Find and Install…
3.) Select: Search for new features to install
4.) Mark: “The Eclipse Project Updates” and click Finish. (url if needed)
5.) Expand the tree “Eclipse 3.3.2″ or newer.
6.) Find: “Eclipse Java Development Tools”, Mark and install.

This is what you do.
1.) You will need SVN Ant, and for some actions it help to add the jakarta regexp, jakarta oro, commons, commons-net packages. To make it simple, grab this zip file.
2.) Open “Flex folder”/plugins/ and create a folder “svnant” and place all the files.
3.) Open Flex -> Preferences -> Ant -> Runtime
4.) Select “And Home Entries” and then “Add External JARs…”
5.) Select all the JAR files you copied to /Flex Builder 3/plugins/svnant/
6.) Create a new project in Flex. Place theĀ build.xml file in the project root.
7.) Right click on the build.xml and select Open With -> Ant Editor.
8.) Set your properties in the top and then right click on getSVNCode in the “Outline window”, Run As -> Ant Build.

TIP.
ANT scripts can grab properties files and run ANT tasks from other ANT files. So you could setup a structure how to read scripts and unique project data to make it more generic.

Documentation to read.
SVN: http://subclipse.tigris.org/svnant/svn.html
ANT: http://ant.apache.org/manual/tasksoverview.html