Stub methods on any instance of a class in Rspec 1 and Rspec 2

CopyUser.stub_any_instance(:foo => :bar)
user = User.new
user.foo
# => :bar

CopyUser.any_instance.stub(:foo => :bar)
user = User.new
user.foo
# => :bar

Copyallow_any_instance_of(User).to receive(:foo).and_return(:bar)
user = User.new
user.foo
# => :bar