The Unslung firmware uses the OpenEmbedded build system kept in a Monotone repository at monotone.nslu2-linux.org.
Optware packages (formerly known as Unslung packages) are developed and maintained in the SVN repository on svn.nslu2-linux.org which is based on the OpenWrt build system which is based on the buildroot system found on uClibc.org. There was a plan to try and take advantage of the 1500 packages available in OpenEmbedded and try and make them work with the Unslung firmware, but that has proved to be more difficult than first envisioned. So for the short and medium term, Unslung firmware will be built using OpenEmbedded in the Monotone repository, and Optware packages will continue to be built using the home-grown build system in the SVN repository. We are still hopeful that someone with extensive OpenEmbedded knowledge will step forward and work out how to get the OpenEmbedded packages (which assume a different set of base files from what exists in the Linksys ramdisk) to work with the Unslung firmware and root filesystem (which is, by definition, designed to use the Linksys root filesystem to retain the stock product functionality).
The OpenSlug firmware (which is a complete kernel and ramdisk replacement, treating the NSLU2 as hardware board and not re-using any Linksys firmware) is also being built using the OpenEmbedded build system in the Monotone repository. The OpenSlug firmware is immediately able to take advantage of many of the 1500 OpenEmbedded packages.
So, if you are a seasoned embedded Linux developer, then visit the IRC channel and help out with OpenSlug.
If you are an embedded Linux userspace developer with extensive OpenEmbedded experience, then visit the IRC channel and help out with getting the OpenEmbedded packages to work with Unslung.
If you are an Optware package developer, then please continue contributing them to the SVN repository and announce them on the mailing list.
If you are an Unslung user, and want to become a package developer, then look at the Optware Development page to find out how to get started.
If you are a happy Unslung user, then now is the time to upgrade to Unslung 6.x.
If you are an unhappy Unslung user, then let us know why you are unhappy...
If you are none of the above, then it's time to buy yourself an NSLU2, load the Unslung firmware onto it, and join the fun :-)
PS: if you would like to support nslu2-linux, you might consider a donation. (Who updates the 'donations & sponsors' page?)