This is a script I wrote to create an ipkg package file of an installed package on the palm pre. If you give it no parameters, it will build ipkg files for all installed packages.
Install it to somewhere on your palm, cd to /media/internal/ and execute it. It will create an ipkg file for each installed package (including the packages by palm). Then download them, put them on the other palm and install there what you need. This will only work if you a) did not install preware so far or b) move the directory /media/cryptofs/apps/etc/ipkg temporarly to another location (because if preware is installed it will have MD5 checksums of each package and ipkg will refuse to install the backup packages - they have other checksums). Install a package by: ipkg -o /media/cryptofs/apps 'package'.
However - use at your own risk. You might also just backup some packages, you can pass a package name to the script, it will then only create a ipk file for this package. A list of packages can be fetched by: ipkg -o /media/cryptofs/apps list_installed.
Currently it fails with some packages (e.g. with preware and some services).