I think I have cracked the spam email problem, and I believe that the
method is patentable. I don't have the funds to patent the idea on my
own, and if I wrote the application myself I'm sure I'd make some
novice errors.

I am looking for 5 online businesses that give the impression they
would welcome submissions of ideas, and if they like them they would
deal with the patent side of things (at least) for a profit share, or
just for free.

I am not interested in anything that would cost me more than an email.

I would also welcome any comments on how I could publicly disclose my
idea (so that it would legally be seen to be "publicly disclosed") in
such a small way that no-one would notice, and therefore after one
year the idea would not be patentable by anyone else.

"An inventor cannot receive a United States patent for an invention
publicly disclosed more than 12 months ago. "
http://www.patent-ideas.com/patents.htm

Robert...

I'm not sure if this is applicable or not, but I've used
self-mailing to lock in copyrights for music I've composed
by mailing a copy, or copies, of the taped music to myself,
never to be opened unless there is a claim that goes to 
court. The postmark constitutes dated proof.

I don't know if this satisfies the concept of 'public 
disclosure', but it certainly proves your origination
of the idea, assuming you can mail yourself a uniquely
identifiable description of your concept.

sublime1-ga

Second thoughts...

Perhaps a small notice in a legal newspaper, such as
those entered in conjunction with a name change, would
satisfy the concept of 'public disclosure'. No one
really reads these but the lawyers, but it still amounts
to 'public' disclosure. You can keep copies of the 
newspaper clippings, as well as the self-mailer.

I'm not sure if you need a lawyer to make the entry
in this type of newspaper.

I wish it were as easy as copyright! Copyright is free and automatic,
and makes life easy for writers and artists. Inventors have to spend
thousands of dollars to protect their ideas, and that's just for a US
patent. Then they have every other country to worry about...

You are about to make the BIGGEST error of your life.  If you disclose
your idea in anyway (print, on TV, etc.), you immediately lose ALL
patent rights in Europe and most of the world.  Also, if you disclose
your invention in writing, no matter how quietly, one year later YOU
will lose all your patent rights in the USA.  This is called a 102b
rejection by the US Patent Office.  So DONT do it.  Do not disclose
your invention to anyone, or you will lose your patent rights.

Now for your wish to have your invention patented by a pro-bono or for
a share of the royalities.  This is also a very bad idea, but if you
have to, make sure the person is a "registered by the USPTO".  There
are a lot of patent promotion companies that will gladly take your
money.

Be careful.  If it is so valuable, then you should invest your own
money.

Copyrights are easy.  Trademarks are a bit more complex.  Patents are
down-right tricky.  If you do indeed have the magic bullet for killing
spam, you then have the recipe to turn lead into gold or water into
gasoline.  Get some respected referrals to a good patent attorney. 
Any money you spend will be returned more than a thousand-fold, if you
really have this solved.

Also, the problem with a patent is that you must divulge the details. 
Thus, you can rest assured they will be stolen and you will have to be
in constant legal batlles.  I think that's why Coke's recipe was never
patented.  They never wanted to divulge it.

Oh well... Asked at a few places, nobody was even slightly interested,
so here it is:
http://skelton.id.au/email-spam-solution.html