debian-installer rc1 is going to be officially announced next week. However, the netboot images are already available. I'm now looking for people who are interested in testing these installer images on ARM and MIPS based machines.
If you have a spare ARM or MIPS machine or want to reinstall your machine for some reason (for example to move from arm to armel), please see my messages on debian-arm and debian-mips for more information.
I've used this opportunity to update all my installation instructions to lenny. See here for Debian on Linksys NSLU2, Thecus N2100, QNAP Turbo Station, HP mv2120 and Cobalt.