Robert C. Rodriguez wrote a nice post on his blog giving some WordPress security tips. To summarise he suggests:

• WordPress Version - Always a good thing to do, however, becareful how you go about doing this; if you remove the global WP version this may affect some plugins and the core WordPress functionality.
• Keep Everything Updated - yup…
• Backup, Backup, Backup! - yup…
• Login Lockdown WordPress Plugin - This plugin logs incorrect login attempts. Could be useful and something we haven’t mentioned on BlogSecurity before. Nice suggestion.
• WordPress Scanner - Of course, we totally agree with using BlogSec’s online wp-scanner service :)
• Prevent Directory Listing - yup…
• Protect Your WP-Admin folder a little more - yup…
• Contact Form - yup…
• Passwords, we don’t need no stinkin passwords! - Choosing a good password and having seperate user accounts for different functions is critical!
• Check your blog, at least daily - yup, not a bad idea.

I really like the way RR wraps up his post:

Securing your WordPress blog is very important, considering the amount of time you’ve put into it.

As blogging explodes, security is always playing catch up. In short, great article, keep it up RR.