First pass at Git (+ Gitweb) integration with FogBugz. Notes in comments.

post-receive.sh

#!/bin/bash

# Git hook to link a commit's BugzID in Fogbugz.
#
# Instead of a filename, script populates URL with repository name.
# This saves us needing to configure a repository per-project in Fogbugz.

# Description, first word in file should be repository-name.git
DESC=description

# Sed Regex - Pull repository name from cwd in case description fails.
PATH_RE="^\/repos\/\(.*git\).*"

# Bash Regex - Pull BugzID from commit msg. Should yield '123' for:
# 'BugzID  :  123', 'BuGsId: 123', 'bugid:123', 'bugzid     :123zzz'
BUGZ_RE=".*bugz?s?id\ *:\ *([0-9]+).*"
# ...Once we enable case insensitive regex matching
shopt -s nocasematch

# Fogbugz URL
FB_HOST="your.fogbugz.host"
URL="http://$FB_HOST/fogbugz/cvsSubmit.asp?ixBug=<BUGZID>&sFile=<REPO>&sPrev=<PREV>&sNew=<NEW>&ixRepository=14"
BUGURL="https://$FB_HOST/fogbugz/default.asp?"

# We need curl or wget
get_downloader() {
    CMD=`which curl`
    if [ $? -eq 0 ] ; then
        return
    fi

    CMD=`which wget`
    if [ $? -eq 0 ] ; then
        CMD=$CMD" -O -"
        return
    fi

    CMD=""
}

# Attempt to get project name, first from description, then path
get_project_name() {
    if [ -e $DESC ] ; then
        read REPO < $DESC
        REPO=`echo -n $REPO | sed 's/ .*//'`
        if [[ $REPO =~ git$ ]] ; then
            return
        fi
    fi

    cwd=`pwd`
    REPO=`echo $cwd | sed "s/${PATH_RE}/\1/"`
    if [[ $REPO =~ git$ ]] ; then
        return
    fi

    REPO=""
}

# Retrieve Bug numbers from BugID/BugzID in commit message
# Multiple BugIDs should be entered one-per-line.
get_bugzid() {
    local rev=$1
    BUGZID=()

    while read msg ; do
        [[ $msg =~ $BUGZ_RE ]] && BUGZID[${#BUGZID[@]}]=${BASH_REMATCH[1]}
    done < <(git cat-file commit $1)
}

get_downloader
if [ "$CMD" = "" ] ; then
    echo "No downloader available to send GET request"
    echo "Not sending commits to Fogbugz"
    exit 0
fi

get_project_name
if [ "$REPO" = "" ] ; then
    echo "Unable to retrieve repository name"
    echo "Not sending commits to Fogbugz"
    exit 0
fi

# Main loop - get and submit commits to specified BugzID
while read PREV CURR REF ; do
    LAST=${PREV:0:7}
    # PREV is the remote HEAD for the branch. We need to walk the commits
    # between PREV and CURR and get / submit the BugzID foreach.
    for COMMIT in `git rev-list $PREV..$CURR | tac` ; do
        COMMIT=${COMMIT:0:7}
        get_bugzid $COMMIT
        if [ "${BUGZID[0]}" = "" ] ; then
            echo "No BugzID for commit $COMMIT"
            LAST=$COMMIT
            continue
        fi
        for BUG in ${BUGZID[@]} ; do
            GET_URL=`echo -n $URL | sed -e "s/<BUGZID>/${BUG}/" -e "s/<REPO>/${REPO}/" -e "s/<PREV>/${LAST}/" -e "s/<NEW>/${COMMIT}/"`
            [[ $BUG =~ ^[0-9]+$ ]] && $CMD $GET_URL > /dev/null 2>&1
            if [ $? -eq 0 ] ; then
                echo "Added revision $COMMIT to $BUGURL$BUG"
            else
                echo "Warning: Unable to GET $GET_URL using $CMD"
            fi
        done
        LAST=$COMMIT
    done
done

Second revision allows for multiple bugs per commit, one per line.