Hi Aric,
Latest entry on Planet Debian is about http://weblate.org/ which could be a good candidate according to its about page :
Weblate is web based translation tool with tight Git integration. It features simple and clean user interface, propagation of translations across subprojects or automatic linking to source files.
List of features includes:
Easy web based translation Propagation of translations across sub-projects (for different branches) Tight git integration Usage of Django's admin interface Upload and automatic merging of po files Links to source files for context