I'm not sure how or where I started with this, and it certainly isn't for everyone, but some of you may find this useful.
OptWare is better known as part of NSLU2-Linux - it's a very simple and very lightweight package manager designed to be integrated on top of embedded linuxes. Basically it's perfect for the Kindle although the repository is rather dated...still great for installing nano, wakelan, bitchx, and other fun toys to use from KiTerm.
...however, there's a bugbear. The existing versions of OptWare expect a version of wget that supports the "--passive-ftp" option, and the Kindle's BusyBox simply doesn't. Took enough work to fix this that I figured it was worth posting.
If you'd like to fiddle with this, here are the (slightly modified) instructions originally available at: http://www.nslu2-linux.org/wiki/Optware/HomePage
Note that you can't install packages to the main partition (/mnt/us) as FAT doesn't support symlinks.
#First, remount root as read/write
tar -xOvzf ipkg-opt_0.99.163-10_arm.ipk ./data.tar.gz | tar -C / -xzvf -
mkdir -p /opt/etc/ipkg
echo "src cross $feed" > /opt/etc/ipkg/feeds.conf
# Usage (with nano as example)
ipkg install nano
You may wish to edit your /etc/profile to make the above PATH changes permanent.