For Anyone using DoubleTwist to sync their iTunes music, the latest update brings wireless syncing.
Android Central have reported that this can be bought for just 99 cents at the moment for the first 10,000 users.http://www.androidcentral.com/doubletwist-update-brings-wifi-syncing-airsync
"DoubleTwist has just been updated with the long-promised and highly-anticipated wifi syncing feature, which has been dubbed "AirSync." Unlike the player itself, which is free, AirSync is an add-on that will run you $4.99 (or 99 cents for the first 10,000 users), you will see a link to purchase it when you start up the updated DoubleTwist Android player."
I've just bought it myself and am currently syncing my Nexus One wirelessly. Easy to setup and no more looking for my USB cable when I add new tracks to my Nexus One! :D
The app can be found in the Android Market, just search for "AirSync".