Do you mean comment spam or just a bunch of referrer spam links listed on your stats page?

For referrer spam, you will always have a problem because you can't stop people from linking to your site.

As long as they are not spamming you with comments, then you're alright. there's nothing else you can do to prevent people (ehem, bots) from linking to your site.

Thanks for the reply. I wrote from my Blackberry so it didn't come out as clear.

They're not really links that people click. They're gambling sites that hit a large number of my posts, but are only logged by B2. Google and sitemeter don't count them.

I didn't have this problem before a couple of months ago and had a little higher traffic then.