I had troubles to get rcov working with the latest rspec2 release (since beta23 and now 2.0.0.rc). I got the same error every time:

`require': no such file to load -- spec_helper (LoadError)

But luckily, somebody found the problem and it is extremely easy to fix. Just add -Ispec to your rcov task. The rake spec:rcov does not work for me (as it needs to be fixed). So i added my own task (add this code to the end of Rakefile or add in a seperate file rcov.rake inside lib/tasks) :

desc  "Run all specs with rcov"
RSpec::Core::RakeTask.new("test_cov") do |t|
  t.rcov = true
  t.rcov_opts = %w{--rails --include views -Ispec --exclude gems\/,spec\/,features\/,seeds\/}
end

and then you can run the task by typing

> rake test_cov

in your rails root folder.