Have look at the Its All Text plugin for firefox ...

https://addons.mozilla.org/en-US/firefox/addon/4125

I wouldn't know about Thunderbird - this might help,

http://globs.org/articles.php?pg=2&lng=en

but better still try Gnus :-)

atb

The buffer works in the normal way: emacsclient is asked to edit a file,
and you get a buffer for that file (normally a new buffer).  You can
configure how the buffer's mapped onto a frame (whether you get a new
frame, new window, etc.) by configuring the "server" group.

I have been using a similar script for several months.  The script calls
emacsclient with either -c or -t depending on the value of $DISPLAY:

    #!/bin/sh

    # Set up locale environment, but only if LANG is currently unset.
    if test -z "${LANG}" ; then
            # First clear off any locale related environment vars.
            __junk=""
            unset __junk `env | sed -n -E '/^(LANG|LC_[A-Z]+)=.*$/ s/=.*$//p'`

            # Then set the preferred locale variables for Greek text.
            export LANG="C"
            export LC_CTYPE="el_GR.ISO8859-7"
            export LC_COLLATE="el_GR.ISO8859-7"
    fi

    # When ${DISPLAY} is non-empty, assume it's ok to spawn a frame with
    # the -c option of emacsclient.
    if [ -z "${DISPLAY}" ]; then
            frameopt='-c'
    else
            frameopt='-t'
    fi

    # Try to fire up some version of emacsclient.
    # The first one that works will terminate this script.

    test -x /opt/emacs/bin/emacsclient && \
        exec /opt/emacs/bin/emacsclient ${frameopt} "$@"
    test -x /usr/local/bin/emacsclient && \
        exec /usr/local/bin/emacsclient ${frameopt} "$@"
    test -x /usr/bin/emacsclient && \
        exec /usr/bin/emacsclient ${frameopt} "$@"

    echo >&2 "emacsclient-wrapper: no emacsclient found."
    exit 1