There is an rpm of realplayer 10 available from
real.com. You might also do a search on
freshrpms.net. You can also install mplayer and the mplayer win32 codecs pack, this works quite well, again there is
an rpm for mplayer at the
mplayer website, also do a search on
freshrpms.net or a similar site.
EDIT: What version of Red Hat are you using?