I came across a new plugin for WPMU which I think a few of you may find very usefull: Manually approve members on local install. This was made to get around the issue of no activation emails being sent from the local server.
No idea yet if it helps stop splogs though. Give it a whirl!
Thanks for the nod Andrea. I see you on the .org site a lot now that I am digging into a few WPMU projects.
I don’t think it is going to stop splogs, but I got a hint from somewhere (probably you!) to rename wp-signup.php and that helped tremendously.
Plugins are customizable and flexible. You can customize Plugins, You can add new Plugins, as much as you want and you can deactiveta them in case you don’t need them or a better Plugin is available arond.