link_to_remote

This is a neat trick: (ajax-version)

link_to_remote('submit', :url => {:action => 'blabla', :id => 
'optional'}, :submit => "id_of_element_around_your_checkboxes")

The important part is the :submit option ofcourse, just wrap the 
elements you want to submit in a <div> (or whatever) and everything in 
it will be posted as if it was in a form.
Very usefull for posting rows of a table, because you can't put a form 
around a complete row. Or for posting something that's inside a form 
(forms in forms are not allowed)