The following steps are tested in T-Mobile G1 with Android 1.5, should be working with other Android phones and other versions of Android.
The first few steps are to obtain the direct link of the Youtube video easily.
Open any Youtube video you want to download, let it loads a bit and then press "Menu" and select "Share"
Select "Messaging", ( Other applications will also work, but I choose the simplest)
Long press on the link "http://www.youtube.com/watch?v=**"
If you get "Copy all" as the only option, press "Back" and try again to get more options.
Select "Cut all" and press "Back". (Since you have cut all the message, there is no hassle cancel the empty message)
The remaining steps are to download Youtube video on KeepVid.
Open "Browser" and go to http://keepvid.com/ (it is convenient to bookmark it).
Click on the URL bar on the KeepVid site and long press to "Paste".
Click "DOWNLOAD" on the KeepVid site.
If you happen to obtain Error as a result, press "reload the page" and try again.
The best case is to obtain ">> Download << (video.mp4 - High Quality 480x360)", that's the best version for G1. If it is not in the list, press "Menu" and then "Refresh" to try again. Sometimes I have to try more than 10 times to get that particular link.
Press ">> Download <<" and the download should start
After the download completed, remember to move it to a desirable folder and rename it since the default name is "video.mp4"
That's the simple and free way to download Youtube videos in Android phones.
wenjiun from CodeAndroid Malaysia