Array or Hash in collection_select?

Hi

I have an array of string and I want to use it in collection_select
rails function..

['cassiano', 'roloff']

to use in...

<%= collection_select 'form', 'field', @my_array? %>

Thanks for help

Cassiano,

<%= select_tag "field", options_for_select(@my_array, @my_array[0]) %>