If you are using your Android phone to view Youtube videos regularly, then this is a must-have app for you. Tubemate is probably the most popular, and personally I think the fastest & most feature rich YouTube downloader available for Android.
It allows downloading in multiple resolutions, ranging from 3gp to HD 720p/1080p resolution, conversion to MP3, saving favourite videos to your YouTube account, and pause/resume downloads.
A word of caution, the Android Market has multiple apps which have similar names, and are imitations of this awesome app. They may not work as well as TubeMate, and may also prove harmful for your device. Hence, we recommend you point your browser to the the Tubemate website, as it is not available in the market.
After installing this app, I have realized that my collection of HD music videos & concerts on my phone has been steadily increasing :) Do give it a try, and share your thoughts in the comments below. I guarantee you will love this app. Download apk Tubemate 1.05.24