Found great summary of mod rewrite here

http://stackoverflow.com/questions/286004/hidden-features-of-modrewrite

I aways forget the params for mod_rewrite so here is the summary

• [R] force a redirect (default 301)
• [R=302] force a 302 redirect
• [L] stop rewriting process (see note below in common pitfalls)
• [NC] case insensitive matches