For those that can't get You Tube button to work on the Internet Page,
My hack way to get YouTube to work:
Install YoutubePlay (
http://forum.xda-developers.com/showthread.php?t=385227)
Open up Regedit
GO to:
HKLM>Software>HTC>Manila2D>InternetWidget>Customiz ed>0
Changed CustomizedURL to
\Program Files\youtubeplay\youtubeplay.exe
That will launch the Youtubeplay app.