TubeMate (also called YourTube) is an open source YouTube video downloader. It looks and works exactly like YouTube Video Downloader except that it's only 50 KB in size instead of 1014 KB. That makes TubeMate a much better choice for phones with limited memory.
TubeMate lets you search for and download videos from YouTube for off-line viewing. It's not a video player, use your phone's file manager to navigate to the downloaded video and click on it to open it in the phone's media player. You can chose where to download the video. Either E:, memory card or the video folder should work on most phones. You also need to choose what format to download the video in. Most modern phones can handle at least MP4 (H.264 360p) but if videos downloaded in that format don't play try the lowest quality option, 3GP (MPEG-4 144p).
The app is unsigned so you will get a lot of prompts to allow it to access the memory card. You can get rid of most of them by changing the phone's settings to allow the app to access memory. The settings vary with phone make and model. On Nokia S40 phones go to "Apps and Games" then "Application sett.", then "Applicat. access", then "Data access", where you need to set both "Read user data" and "Add and edit" to "Ask first time" instead of "Ask every time".
Type: OpenSource download code
Vendor: Oleg Derevenetz
Data Connection Required: Yes
Minimum Java ME profile: MIDP 2.0
Screen Size: All
Touchscreen support: Yes
Reported working on: LG Rumor Reflex, Nokia Asha 303, Samsung GT-S8500 Wave,
Reported NOT working on: Samsung Factor
Please let us know in a comment if it works or not on your phone
The app "TubeMate" (50 KB) is ready to download or send to your phone as filename: "TubeMate".