Hi,
 I've written a gem command plugin, gem grep. You'll need the latest
rubygems v 1.3.2 to try it out.
gem grep enhances gem search in three ways:

1. Displays results in a well formatted ascii table. Allowing for
detail while still maintaining one gem per line.
2. Specify a list of any gemspec attributes you'd like to see for the
results want to see with a --columns option.
3. For local searches, search any number of gemspec attributes with a
--fields option.


Some examples: http://tagaholic.me/2009/04/23/how-to-write-a-rubygem-command-plugin.html#examples
Homepage: http://github.com/cldwalker-gem_grep

Install it with: gem source -a http://gems.github.com && sudo gem
install cldwalker-gem_grep

Enjoy!
Gabriel