Back in High School, my class had a shirt printed out with all our
names on the back, in the shape of the year, "99"

so basically, if you see it from afar, you see 99, but looking closer,
you can see individual names. does any software avaliable do this? I'd
like to design my website with the same idea, and don't really want to
do it manually.

Most high-end DTP or graphics software will do this - you would create
a polygonal text box or frame (instead of a rectangular text box) in
the shape of the 99, and then fill it with the names text. Vector
graphics software would probably allow you to take 99 in a font,
convert font outlines to curves, and then fill the area bounded by the
curves.

Probably *not* practical on a website - remember that you have no
control over the browser or settings used by website visitors, some of
whom may be using a text-only display, speech synthesis or tactile
braille output rather than a screen.

Owain