Vimeo has introduced the capability to convert all your existing Vimeo uploads to a mobile video version, however this Mobile video feature is currently limited to Vimeo Plus members.
Owners of an iPhone, iPod Touch, Android, and Palm Pre smartphones can visit www.vimeo.com/m today to browse the Mobile site and watch Vimeos mobile videos. Plus members can start transcoding their Vimeo videos by logging in from their smartphone and clicking the ‘Generate Mobile Videos’ link. This is a smart thing for Vimeo to do, in order to reach a larger audience it’s logical to expand their site to the growing smartphone space.
Prior to mobile videos being available Smartphone owners could upload their videos to Vimeo, but would need a Browser with a minimum of Flash 9 support to watch the videos, typically on a home computer.
Source: Vimeo Staff Blog