allowing news out

Hello,
I've got an ipfilter firewall that i'm tightening down. I'm allowing out
only specific services, right now the one i'd like to let out is news, port
119 i believe, ntp is another one, port 123 i think.
For news i've got internal clients using outlook express to connect to
my isp's nntp server, but the firewall isn't letting the traffic out or in,
it seems as if the source ports change, ntp is the same way. Any
suggestions?
Thanks.
Dave.