: I wanted to make use of an old 486 I have.
: I just want to use it as a web browser.
: Is Linux a reasonable thing to use for this app?
Yes, but web browsing with a modern browser may eat up more memory than
you'd like. X and a browser will run in 16mb, but may thrash virtual
memory a bit. Get 32mb or more of old memory parts for the '486 if you
can. Again, not so much for X, as for the web browser, which can suck
down 10 or 20 megabytes just loading a page or two. FWIW, the old
netscape 4.7x releases consume about half that of a new mozilla release
for loading the same page, just eyeballing it by use of "top".
: where would I find a old version of Linux for a 486 computer
: (with installation instructions)?
Hmmmm. Last time I ran a full linux on a 16mb 486, it was
redhat 5.6, and before that, early slackware. I have no idea
if those releases still exist. Luckily, you don't necessarily
need an old release; slackware can be installed very lean indeed,
but instructions for doing so are maybe a problem.
There are a wide variety of linux releases listed at
http://www.ibiblio.org/pub/linux/distributions/
some of which purport to have easy install instructions
and a small footprint (though they normally seem to mean
disk footprint, not memory footprint, but still). Some
that look promising are
http://www.scrudgeware.org/
http://www.ibiblio.org/peanut/
ftp://ibiblio.org/pub/Linux/distributions/vectorlinux/
in addition to the old standard
ftp://ibiblio.org/pub/Linux/distributions/slackware/
You have to beware, since some of these may be "optimized" by
compiling them for pentium-and-later-only CPUs, and so forth.
But you should be OK with slackware, and as I recall, peanut
linux has a '386 and newer iso image as well as a '586 and newer one.
All in all, if it were me, I'd probably try scrudgeware, since
it seems to have the right goals in mind and may have done most of
the work of working on small systems, and fall back to slackware
if all other promising leads fail. Or, just cut to the chase
and start with slackware :-). Depends on how much fussing around
you want to do, and how comfortable you are figuring out which
packages you need and which you can leave out.
Note in passing, a lot of those distributiosn have the goal of fitting
on a floppy, or to be the base of embedded development, or for use of an
old box as a router, or other really REALLY small environments. But
of course, the really small ones don't normally have X, sigh.