I like niftytelnet generally (for ssh) and don't really mind that I
have to type pathnames into the scp interface. Probably
because that is what you have to do in unix command line scp,
too.
Now that I use Mac OS X almost exclusively, I just ssh/scp from
the terminal app.
Anyway, the author of MacSSH (a ssh 2 client for Mac OS 8/9)
has a shareware thing called MacSFTP that I haven't tried, but it
might suit your needs. The direct link for download is here:
https://openacs.org/bboard/q-and-a-fetch-msg.tcl?msg_id=0003Nu&topic_id=11&topic=OpenACS
Also check http://versiontracker.com when you need Mac
software. I came up with http://versiontracker.com/moreinfo.fcgi?id=12468&db=mac as another option.
Enjoy,