Tonight I have tagged 3 rc releases of our 3 anti spam modules which have had a couple API changes. If you are trying to setup a site with mollom, recaptcha or your custom spam protection module these updates will hopefully provide a stable platform.
Both these spam protection methods (mollom and recaptcha) are compatible with the new userforms (0.2rc2 to be released soon). Previously your only option was mollom, now reCaptcha has been adapted to implement the userforms required code.
As always please report any errors to open.silverstripe.org. Please make sure you tag issues under the correct component (spamprotection, mollom and recaptcha respectively). The module documentation page as well as the internal documention is being updated as we speak (forgot to update the internal files before tagging sorry :))