There doesn't seem to be a man page on ulimit in 1.6.
I get this instead:
ULIMIT(3)                 NetBSD Programmer's Manual
ULIMIT(3)

NAME
     ulimit - get and set process limits

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <ulimit.h>

     long int
     ulimit(int cmd, ...);

DESCRIPTION
     The ulimit() function provides a method to query or alter resource
limits
     of the calling process.  The method to be performed is specified by the
<etc>

Is the man page missing or removed on purpose?

Michael D. Spence
Mockingbird Data Systems, Inc.