I use Vimeo and find it quite easy to upload from iMovie '11. iMovie has a Share option (Share>Vimeo) that allows a direct upload to Vimeo. This works quite seamlessly in my experience, much the same as YouTube uploads.
I'm actually a Plus member (annual fee $59.95), but you can use the free membership which is fine for most purposes. Here is a link to Vimeo's page showing a comparison between the free Basic Account and Vimeo Plus:
PS Meant to say that there is also a Vimeo iPhone app. You can upload videos directly from the app and also view all your uploaded videos, among other things. I haven't tried uploading from the app but I'm sure it will work fine. Vimeo has been great for me as it basically replaces my MobileMe Gallery which is no longer supported nor available from Apple. I've been gradually uploading my Gallery videos to Vimeo (mainly iMovie trailers), but also use YouTube for some videos on occasions.
Message was edited by: John Cogdell - added PS
I'd like to move from youtube to... well, just something else.
YT offers lots of (unpopular) features, such as setting clips 'private', a basic editor and titler, notification service, watchers stastistics etc.
another option, esp for 'private' usage, are cloud-storage-services as Dropbox or Kim's latest project Mega