I just posted information on changes to DNSWL.org over on DNSBL Resource. Looks like they're moving to a for-pay model, for at least large volume queries. Can't say that I blame them; if it is costing them money to keep their project alive, at some point it seems inevitable to turn to users to help provide financial support. Do any of you use DNSWL.org? I'm not overly familiar with them.