If you find a bug in Calc, send e-mail to Jay Belanger,
There is an automatic command M-x report-calc-bug which helps you to report bugs. This command prompts you for a brief subject line, then leaves you in a mail editing buffer. Type C-c C-c to send your mail. Make sure your subject line indicates that you are reporting a Calc bug; this command sends mail to the maintainer's regular mailbox.
If you have suggestions for additional features for Calc, please send them. Some have dared to suggest that Calc is already top-heavy with features; this obviously cannot be the case, so if you have ideas, send them right in.
At the front of the source file, calc.el, is a list of ideas for future work. If any enthusiastic souls wish to take it upon themselves to work on these, please send a message (using M-x report-calc-bug) so any efforts can be coordinated.
The latest version of Calc is available from Savannah, in the Emacs repository. See http://savannah.gnu.org/projects/emacs.