Don't know if anyone has seen this or not but Zimbra got a good review for netbooks in a CNET review. They were reviewing Web based apps and Zimbra got high marks.

CNET Article

Zimbra is the perfect office Web app for Netbooks. You get e-mail, calendaring, chat, document editing and creation, as well as contact management in one tight package. I gave both the Ajax and HTML versions of the service a spin, and the performance was equally great across all three browsers