b64 is too small a project to command its own website and news, so piggybacks on the Synesis Software website and the STLSoft newsgroup.
The home page is currently at http://www.synesis.com.au/software/b64.html. This may change at some time in the future, but a valid link will always be provided at http://www.synesis.com.au/software.
There are two ways to provide feedback. The preferred way is to post a question on the the STLSoft newsgroup (news://news.digitalmars.com/c++.stlsoft), prefixing your message with "[b64]: ", as in "[b64] Version 1.2 needs another new feature".
Alternatively, you can email direct at the following (obfuscated) address:
m_a-t_t-h_e-w_@ synesis.com.au