ruby-1.9.1-p243 has released. i386 and x64 binaries are available.
And, ruby-1.8.7-p174 and ruby-1.8.6-p369 have also released.
Sorry for late of the preparation of the binaries...
These contains security fix. I recommend to upgrade.
You can get all binaries from "Release".
By the way, ruby-1.9.2-preview1 has released, too.
1.9.2 is scheduled to become the next stable version. This is the first preview of it.
You can get i386 and x64 binaries from "Developping versions snapshots".