Rails 2.0.2 is out, this version fixed the rake rails:freeze:gem problem with RubyGens 0.9.5, this version is a drop-in replacement for Rails 2.0. From the release announcement.
Rails 2.0.2 contains a bunch of smaller fixes to various bugs, no show-stopping action, just further polish. But it also contains a few new defaults. The major change is mysql is no longer the default database. SQLite3 is the new default database, SQLite3 is shipped with Leopard. Use
$ rails -d mysql dummy_app
to set the default database to mysql.