A shell script that uses adb to push fonts onto the G1. Make sure adb is in your path.

push_font.sh

#!/bin/bash

# make sure we have 1 or 2 arguments
if [ $# -ne 1 ] && [ $# -ne 2 ]; then
    echo "usage: `basename $0` font [bold_font]"
    exit 1
fi

adb devices|grep -w device > /dev/null
if [ $? -eq 1 ]; then
  echo "Error: device not found by adb"
  exit 1
fi

echo "Device found"
echo "- Remounting / as rw"
adb remount
echo "- Sending fonts"
adb push "$1" /system/fonts/DroidSans.ttf

if [ $# -eq 2 ]; then
  adb push "$2" /system/fonts/DroidSans-Bold.ttf
else
  adb push "$1" /system/fonts/DroidSans-Bold.ttf
fi

echo "- Remounting / as ro"
adb remount
echo "Done."
echo -n "Reboot device (Y/N)? "
read reply
if [ "$reply" == "y" ] || [ "$reply" == "Y" ]; then
  echo "Rebooting device..."
  adb shell reboot
fi

Instead of this, now you can use Type Fresh!