If you're having problems installing OS X v10.0 on a Beige G3, you're not alone. It appears they may be susceptible to issues surrounding 3rd party hardware and/or previous OS X installs. This thread on the MacNN forums has a good discussion on how to get it installed and running, and discusses some of the issues people are facing.
As is usually the case with situations like this, some are reporting no problems at all; others are having a very difficult time getting OS X installed.
Mac OS X Hints