The tkCVS package is the most popular graphical user interfaces for CVS.
There is a mailing list for discussions concerning tkCVS; to subscribe send a message whose body consists of "subscribe tkcvs-discuss" to firstname.lastname@example.org; if all goes well you should get an automated acknowledgement. Traffic has been almost as high as one message per day in the past but as of Jun 1997, it seems to be more like one message per month.
Cyclic does not (yet at least) support tkCVS as part of our "off the shelf" support contracts, but we are open to discussing supporting it.
I suppose we need to make an explicit disclaimer that the tkCVS distributions listed below are not supported by Cyclic. In most cases we are just redistributing or linking to a distribution provided by someone else, and didn't even help write any of it.
The latest version of tkCVS (for unix) is 6.0 and is available from the Neosoft Tcl Contributed Sources Archive in the sorted/apps/tkcvs-6.0 directory. For a link to the archive, see our tcl page. Note that tkCVS 6.0a, which you might find floating around, was an alpha test release and is older than 6.0.
tkCVS is free software; here are the details.
You will need a copy of tcl 7.x and tk 4.x. Some operating systems (linux, anyway), may ship with these. Our tcl page has more on downloading them.
NOTE: There is a problem using tkCVS 6.0 with CVS 1.9 and wish4.2. When importing a module, you may get an error message: 'Cannot use non-numeric string as operand of "&&"'. This does not occur with wish4.1. You can also issue the "cvs import" command from the command line.
tkCVS expects to be able to run the command "cvs checkout modules". If your modules file does not contain an entry for modules add a line like "modules CVSROOT modules" to CVSROOT/modules (see the CVS documentation for details).
The document Version Control with tkCVS by Gerald Brandt is a very nice introduction to tkCVS aimed at users with no CVS experience. Some of the material covers usage specific to the author's site, but most of it applies to tkCVS installations in general.
The book A Practical Guide to Linux contains a page introducing tkCVS. Because it is only one page, I doubt you'd want to get the book only for the tkCVS content, but if you already have the book, it is worth a glance as it points to those aspects of the tkCVS user interface which are less self-explanatory than others.