I came across this project the other day. Apparently it should work with any SIP-based VoIP client. (They list X-Lite, Gizmo and SJphone.)
I haven't had a chance to test it, but I sure will - they provide a source-form linux version. I may even contribute a gentoo e-build, since so far I couldn't find one...
What makes this project even more interesting to me is the fact that Phil Zimmermann, the original creator of PGP, is behind it.
If you forgot the admin password, you'll need to upload a new firmware to the phone in order to get default settings again.
I first downloaded snom200-3.56z-SIP.bin from http://www.snom.com/firmware.html to my tftp server.
then I created a symlink snom200.bin to snom200-3.56z-SIP.bin
now you need to power on the phone. while the initial text/logo is displayed, press any key. the phone now prompts you for an ip address and a tftp address. enter these, and press OK. the phone will now update it's firmware and boot. you then need to select the country, timezone etc. once this is done, you get a new firmware with factory defaults.
now just point your browser to the snoms' ip address. (while we are here we can check if the bootloader can be updated too)