According to John Lange:
Slackware has "netwatch" which is basically a "top" for network connections. I haven't used it much but it potentially really useful.
Home page here: http://www.slctech.org/~mackay/netwatch.html
Not sure if it ships with other distributions. (does not come with Mandrake)
Also, proftpd now has a "ftptop" which does that for FTP connections.
I use something called "iftop"...
http://www.ex-parrot.com/~pdw/iftop/
If you dig around, you'll likely find an rpm version of it. I found one that was a bit out of date, but it was easy to update the .spec file to build a binary rpm from the latest source tarball.