You can drag a playlist from iTunes and drop it on the "New Playlist" button in the left sidebar in Spotify. I don't know if it works with Genius lists, but it works with "Recently Played" and other dynamic lists.
What format is Playlist Builder using, m3u perhaps?
Re:Spotify vs the US Competition
by SkyMarshal on Monday July 18, 2011 @02:07AM
(#2775275)
.m3u8, all stored in what appears to be /Playlists, though my phone isn't rooted so I'm not sure if that's the highest level of the directory structure.
Same problem on the Android app I just discovered yesterday, all my local playlists are made with a third party app called Playlist Builder, and both PowerAMP and Google Music can use them, but apparently not Spotify. I only have Premium, but it seems Premium is intended to enable local music and playlists just not sharing and streaming...