YouTube hosted, streamed on your site. If you have a lot set it up like you would any HUB on a site. I like to embed in relevent text and/or have a page with transcript for each video. The transcript is likely the best way to get your video indexed for search. It is also neccessary for accessability to handicapped users.

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Follow me on Twitter! On the Trail with SOSG How I became a Social Media Convert and Twitter and Agents of Influence and now regular poster at Cloudmixer where We're Mixing New Media Ideas.