YouTube has released brand new set of banners that you may keep in your website to promote your channel in YouTube.
You can either use them to link to your main YouTube channel (ex:http://www.youtube.com/user/google)
or
link to your YouTube subscription page (ex: http://www.youtube.com/subscription_center?add_user=google)
The following are the some of the YouTube buttons available on this YouTube page for download.
The image buttons are available in all possible sizes (small, medium & big) for your site.
YouTube Banners:
Add these buttons to your website to make yourself popular on YouTube.
You may also grab Twitter, Facebook, MySpace Ribbons For Your Website