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I have a problem with the interaction of marks and the latex twocolumn
style.  I wonder if anyone has solved it.

I am trying to produce a list of participants at a conference.  The code
I have done works except for the marks, which simply don't work.  The
code is

\documentstyle[12pt,twoside]{article}
 \oddsidemargin .2in \evensidemargin -.2in
\textwidth 6.5in
\headheight 10pt \headsep 20pt
\textheight 8.5in

\makeatletter

\def\ps@myheadings
{\def\@oddfoot{}\def\@evenfoot{}\def\@evenhead{\hbox to .5\hsize{\sl
\firstmark\hss}\rm \thepage\hfil}\def\@oddhead{\hfil\rm\thepage
\hbox to .5\hsize{\hss\sl \botmark}}}
\makeatother

\pagestyle{myheadings}
\thispagestyle{empty}
\begin{document}
\twocolumn
[\LARGE
\begin{center}
LIST OF PARTICIPANTS
\end{center}
]
\vskip20pt

\catcode`\^^M=13
\parindent=0pt
\let^^M=\par

\def\addressbox#1[#2]%
{\vskip 10pt plus 1fil
\parbox{\hsize}{#1}\mark{#2}}

and then there is a list of names and addresses in the form

\addressbox{
Prof. Michael Barr
Dept of Mathematics
McGill University
Montreal, Quebec
CANADA H3A 2K6
barr@triples.math.mcgill.ca
}[Barr]

What happens is that the odd numbered pages work right, but the even
numbered pages get the name at the top of the SECOND column, not the
first.  I then tried Mittelbach's \multicols environment and what
happened was that on most pages I got a warning that material had been
moved to the next pages and that footnotes might be wrong.  Well, not
only footnotes, but also marks are wrong.  For every such odd page, the
\botmark turned out to the first name on the next page.  Has anyone
faced---and solved---this problem?

Michael Barr