Can I create a drush make file and installation profile from existing site? I have an existing Drupal site, that I would really like to be able to put entirely (or as much as possible) into code and use drush, a git repo, and installation profiles to be able to properly track my code and do rebuilds on my site. Is it possible to create this from an existing Drupal site. If so what are the steps to achieve this?
Profiler and Profile Builder, while useful, are for building a new profile using tools and libraries.  If you would like to convert an existing site into an installation profile, please see: 

http://drupal.org/node/1368242

This issue contains a Drush command to build a Drupal 7 installation profile from an existing site.  The issue is marked as "needs work" because the code templates for Drupal 6 are not in place yet, but if you're working on a D7 site, it should do the trick for you.