I should point out though that if I was a new member and didn't get access for 5 minutes, I'd be fairly pissed... and if you let people in before the rsync, you'll have half of your images broken or bad page loads (one server will allow, the other will deny) if you're using basic authentication.
You might want to consider other methods of validation, like a gateway/session cookie approach, or perhaps mod_auth_mysql or such.
