What you want is a message queue solution. These do exactly what you
want. Your main script can dole out tasks, and workers pick the tasks
up, complete them, and report in. An added bonus is that this can give
you some parallelism, potentially speeding up your search.

Take a look at Starling:
http://rubypond.com/articles/2008/07/17/the-complete-guide-to-setting-up-starling/

Drb:
http://chadfowler.com/ruby/drb.html
http://segment7.net/projects/ruby/drb/introduction.html

AP4R:
http://ap4r.rubyforge.org/wiki/wiki.pl?HomePage

in addition to Rinda, bj, beanstalkd, sparrow, rq...

-- Mark.