I've used Ivy http://ant.apache.org/ivy/ with SVN to manage dependencies for Actionscript projects in the past. The library I used was ivysvn: http://code.google.com/p/ivysvn/
It seemed to work pretty well, the svn repository hosted versioned binary .swc files for each Actionscript library and I would pull them down into individual projects using ivysvn ANT tasks.
Is there a similar workflow like this for git? I'm guessing it might be a little more complicated (maybe using git submodules) since git can't really pull down individual files as far as I know. I'd also probably need another ANT task specific to git like the third party ivysvn libary. Is there a better way to manage 3rd party dependencies with git besides ivy?