There is a bug in Fedora 12 that breaks XBell() support (don't know if it will get fixed), which means xterm can't beep.  There is support in xterm for XkbBell(), but it needs a header file from libxkbfile-devel to build.  It is auto-detected by configure, so just adding libxkbfile-devel to the spec file BuildRequires solves the problem.

There is a bug in xterm that keeps it from creating the necessary X atoms for beeps; here is a one-line patch (against xterm-255, but obvious patch for any version).  I've also sent this patch upstream.

diff -urN xterm-255-dist/misc.c xterm-255/misc.c
--- xterm-255-dist/misc.c       Thu Jan 21 03:34:58 2010
+++ xterm-255/misc.c    Fri Feb 26 08:25:14 2010
@@ -800,7 +800,7 @@

     for (n = 0; n < XtNumber(table); ++n) {
        if (table[n].value == which) {
-           result = XInternAtom(XtDisplay(xw), table[n].name, True);
+           result = XInternAtom(XtDisplay(xw), table[n].name, False);
            break;
        }
     }

With this patch and the BR added to the spec file, xterm can beep again in F12.