jCVS is a java application (not applet) that speaks the cvs protocol to the cvs server. This allows for remote checkouts and updating of sources. jCVS is a cooperative, free internet project.
The most appropriate mailing list is info-cvs which covers CVS itself in addition to jCVS. To subscribe send mail to info-cvs-request@gnu.org. Traffic has been something like 5-11 messages per day.
The newsgroup for jCVS (and other version control systems) is comp.software.config-mgmt.
If you are using jCVS 4.6.1 connecting to CVS 1.9.10 or later using pserver, the "Test Connection" dialog box will not work. Instead, use checkout with tracing turned on.
Version 4.6.1 (and earlier, presumably) have a serious bug in that the "Project | Update" menu can destroy your sources. The fix is to upgrade to jCVS 4.7.2 or later. The workaround is to use "Selection | Update", and disable the "Project | Update" menu
Consult the Author's page for more information on jCVS. y