I wrote my first open source ruby gem today. It's a pretty simple idea - supply a Gemfile or Gemspec and the gem tries to determine which license each included library falls under, and thus whether you have any requirements you must abide by with your own project. Here's an example output:

>> deriving_license ~/Code/rails_sample_app/Gemfile
Determining license for rails:
Trying from_gem_specification strategy...FAILED
Trying from_scraping_homepage strategy...SUCCESS
Determining license for adt:
Trying from_gem_specification strategy...FAILED
Trying from_scraping_homepage strategy...FAILED
Trying from_license_file strategy...CUSTOM
Determining license for app_constants:
Trying from_gem_specification strategy...FAILED
Trying from_scraping_homepage strategy...SUCCESS
Determining license for bcrypt-ruby:
Trying from_gem_specification strategy...FAILED
Trying from_scraping_homepage strategy...FAILED
Trying from_license_file strategy...CUSTOM

...
    
Detected 4 known licenses:
MIT: Expat License (14 instances)[http://directory.fsf.org/wiki/License:Expat]
Ruby: Ruby License (6 instances)[http://www.ruby-lang.org/en/about/license.txt]
BSD: FreeBSD Copyright (2 instances)[http://www.freebsd.org/copyright/freebsd-license.html]
GPL: GNU General Public License (2 instances)[http://en.wikipedia.org/wiki/GNU_General_Public_License]
The following dependencies have custom licenses: adt, bcrypt-ruby, bootstrap-sass, rack-protection, sqlite3

You can grab it from https://rubygems.org/gems/deriving_license or just by running 'gem install deriving_license'. Let me know if it's useful to you, and feel free to fix it up and submit a pull-request!