I just installed Ubuntu 10.04 Lucid Lynx Netbook Remix on a new Asus Eee PC R101. The internal speakers worked, but the headphones did not.

It turns out that this is a known bug in ALSA and has been fixed but not yet released. In the meantime you can get this going by following these instructions:

https://wiki.ubuntu.com/Audio/Instal...aDriverModules

Thanks very much to David Henningsson for the incredibly fast response