YouTube app for Symbian has received an update, version 2.4.10 brings in a few notable improvements: First off, devices running new Symbian OS are finally supported: Nokia N8, C7, C6-01, or even E7.
Also in are higher quality videos, where the source material permits it. Although it still seems that even the highest quality videos on Symbian are lower quality than those played in 'HQ' on Android.
You can also sign in with your Google/YouTube account and use Favorites and other account-specific features.
To download YouTube 2.4.10 for Symbian, point your device's integrated web browser to m.google.com and, choose YouTube.
It's a 2.5 MB download, and will update any previous version you've installed.