Loop through cookbook directories and find out which versions you've got.

cb_versions.py

import os
from distutils.version import LooseVersion as Version

if __name__ == "__main__":
	cb_versions = {}
	for cb_dir in os.listdir("."):
		if cb_dir.startswith("cookbooks"):
			print "Scanning %s" % cb_dir
			for cb in os.listdir(cb_dir):
				if not os.path.isdir(os.path.join(cb_dir, cb)):
					print "Skipping %s as it is not a directory" % cb
					continue
				try:
					metadata = open(os.path.join(cb_dir, cb, "metadata.rb")).readlines()
				except IOError, e:
					print "Failed to open metadata.rb: %s" % e
					continue
				version_line = [x for x in metadata if x.startswith("version")][0]
				version = Version(version_line.split()[1].strip('"'))
				if cb in cb_versions and cb_versions[cb] >= version:
					continue
				if cb in cb_versions:
					print "Replacing %s with new version." % cb
				cb_versions[cb] = version
	print cb_versions