SCSH works well, and it's built on scheme48.

ftp://ftp-swiss.ai.mit.edu/pub/scsh/scsh-0.4.2.tar.gz
and
comp.lang.scheme.scsh

On NetBSD-1.2_BETA (i386 and sparc), all you do is:

$ ./configure
$ make
$ make install

ta da. :)

You will note that SCSH is Olin Shivers's scheme shell, which
has rather good interfaces to UNIX for shell or systems programming.

Print out scsh-manual.ps and scsh-paper.ps, both found in the
same place as the distribution.   Read the NEWS* and TODO* files.
Read doc/big-scheme.txt, too.  All this will give you a good overview
of the features and drawbacks of scsh/scheme48.   The newsgroup
is a good place to discuss bugs and problems, or to contribute code.

The FAQ for comp.lang.scheme also has various pointers to implementations,
information resources and the like.   I don't think there's much there
that's NetBSD-specific, though.

	Sean.