The 2.0 version of CertAid for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The program is included in Internet & Network Tools. This free Mac app is a product of Information Services & Technology. We recommend checking the downloaded files with any free antivirus.
From the developer:
CertAid manages the entire certificate setup procedure for Safari browsers on Mac OS X 10.5 (Leopard), 10.6 (Snow Leopard), and Mac OS X 10.7 (Lion) giving users a more reliable installation experience.
The setup procedure includes installing the MIT CA as well as the user's personal certificate, optionally deleting old certificates, and setting the correct identity preferences via a single, graphical application.
You may want to check out more software for Mac, such as Cooliris Widget, VisComPic or Jhoos, which might be similar to CertAid.