While there are several add-ins for Internet Explorer and Firefox as well as sites like KeepVid that offer better alternatives, I'm offering up yet another method of downloading YouTube videos I recently discovered: A YouTube Search Provider.
To install the search provider follow this link
Once installed, simply copy the video ID of a YouTube Video and paste it into the search bar.
As an example the video ID of this YouTube video (http://youtube.com/watch?v=t4bMM73-qHo) is t4bMM73-qHo. Pasting that into the IE Searchbar and then choosing YouTube Video Downloader (if its not already selected) will start the download.
What's so special about this?
Well, this particular method will work around a proxy that is blocking DNS entries (such as youtube.com).
This is because it uses the direct IP address of rd.cache.l.google.com (most proxies wont block Google.com)
But why not use YouTube's IP address?
Well that works, however it redirects you to another YouTube server that's hosting the specific video (http://lax-v172.lax.youtube.com/ for example). This is a problem, because youtube is in the DNS name (the site will therefore be blocked). Sure you could then go and nslookup the address of that server, then substitute in the relevant IP and the video would download but, that's rather time consuming.
How is this a Vista Problem or Resolution?
Ok, you've got me -- It isin't. I just didn't have any other place to publish this to :(