How to create "cross-backend" python web app

[matt]

Hi all-

I'm trying to port an ajax spell-checker
(http://www.broken-notebook.com/spell_checker/index.php) to use with
the moin moin wiki and have been somewhat successful.  (By successful I
mean I can spell check using the php backend and my python port running
as cgi-bin).

My question is this:  moinmoin runs on many python web backends
(cgi-bin/mod-python/twisted/standalone).  My spell-checker backend runs
as cgi (disclaimer: I've done a bit of php and java(struts) web app
programming, but the last python related web programming I did was Zope
about 5 years ago (does that even count ? ;) )) because that was the
easiest for me to get up to speed on.  What is the best way to write
cross-backend python web apps?  Is there any abstraction I can use?
With cgi-bin, I use the python "cgi" module, which gives me easy access
to form variables, but I'd like to be able to deploy in the other
backends as well.  What's the best way to do this?  Or is a rewrite
required for each one?

thanks

matt