If your Ubuntu Jaunty Alpha or Beta has no keyboard or mouse…
The keyboard and mouse fail to work under a certain kernel. For whatever reason, the kbd and mouse drivers don’t load, and logging in becomes difficult.
Until a fix is sent during the beta testing, the secret is to boot with a different kernel. Instead of the default, which was the server kernel for me, I just used the generic kernel, which was the third option (on a fresh kubuntu install). Then everything works fiine.