[wp-hackers] How to Make Plugin MU-Capable

[Jorge Peña]

Hello, I'm the developer for a plugin (wp-recaptcha) and it has been my
intention (Due to many requests) to make it MU-capable, the only 'problem'
is I haven't gotten around to figuring out what it is that this entails.

Does MU use actions and filters? The main filters I use are:

wp_head - CSS for the reCAPTCHA related things on the blog such as hidden
emails (filter)
admin_head - CSS for the admin settings (filter)
login_head - CSS for the reCAPTCHA on the registration page (filter)
register_form - To display the reCAPTCHA on the registration page (action)
registration_errors - In case the user typed in the wrong CAPTCHA or failed
the test, display the errors (filter)
the_content - Email hiding using MailHide (filter)
get_comment_text - Email hiding for comments (filter)
the_content_rss - Email hiding for the content in RSS (filter)
comment_text_rss - Email hiding for comments in RSS (filter)
comment_form - To display the reCAPTCHA form (action)
pre_comment_approved - To mark comments as spam (action)
preprocess_comment - To check the comment before we post it (filter)
comment_post_redirect - To redirect if the user failed the CAPTCHA (filter)
admin_menu - For the plugin options (action)
admin_footer - For plugin warnings (action)

Or is it even a matter of what hooks aren't available but something else? Or
maybe they are different hooks that I must hook to? I'll gladly figure this
out myself I just don't know where to start, thanks I would appreciate any
help.