Little update: OpenWRT is not completly ready, but at http://code.google.com/p/raspberrypi-openwrt/
it is already working fantastic. Latest infos are given in the newsgroup here: https://groups.google.com/forum/?fromgr ... %5B1-25%5D
OpenWRT is working there without errors, but without all the news features from the real OpenWRT image / trunk. Problem with the orginal is, it does boot, but gives out huge amounts of SD Card errors all the time. And thats already solved in the google project posted above.
So, maybe that does help out others.
Thanks to juanRIOT for kicking my butt to write this down, I am in a lot of work at the moment, sorry!