Android, the most popular os from google.inc, is widely using in mobile phones and other electronic devices. The best feature of android is reported is its great flexibility and efficiency to load multiple tasks at same time. Due to this reason various mobile phone companies have changed their default os to android. The latest phones of 
samsung and 
nokia use this OS too. Today I have some links to download free video players for android devices,especially mobile devices. 
This
  is my personal favorite from available video players. I am using pro  
version of the VPlayer. VPlayer is the best video player for Android 
phones.   Video formats: divx/xvid, wmv, m4v, flv, rmvb, avi, mkv, mov, 
mp4, 3gp,  ts, tp and so on.  Streaming: http, rtsp, mms and m3u(apple 
http  stream, m3u8). If you’re going after a relevant video player using
 the  best consumer experience and interface then 
VPlayer Professional will probably be your ultimate choice.
RockPlayer
  is high performance, almost all formats media player with a lot of  
functions. It saves your time and disk space to transcoding or format  
converting. Just put your video on sdcard or click the URL in 
browser to watch it.
MX
  Video Player – The best way to enjoy your movies.  It plays almost  
every video files with multi-core decoding capability. HD Playback,  
Simple UI,Remembers playback position, Software/Hardware Decoder,  
Subtitles (with custom font, color, size).
Mobo
  Player is one of the best video player available for android phones.  
You can watch any of your videos on a phone without conversion, anytime 
 and anywhere.  You will get the best playback experience and quality.  
 Video player supports: All video formats and Popular subtitle formats  
such as SRT, ASS, and SAA Subtitles built in MKV, MPV, MOV, and others  
Multi-audio streams and multi-subtitles Playlists and continuous play on
  same type files Videos streamed through HTTP, RTSP protocols Media  
libraries and sort videos by type Thumbnail displays of videos.
mVideoPlayer
  is the best video player replacement application available for 
Android,  with a lot of useful and handy features and a nice and clean 
interface  it greatly improves on Android’s built-in video player.  The 
application  is freely available here on the Android market.
BSPlayer
  for Android is a versatile media player for Android smartphones and  
tablet PCs.  Main features: Support for almost all media files (video  
and audio player), such as: avi, divx, flv, mkv, mov, mp4, m4v, rmvb,  
wmv, 3gp, mp3… and streaming content such as http and rtsp. Multiple  
audio streams and subtitles. Playlist support and various playback  
modes.
7. 
Meridian Media Player RevoluteThe  most functional and customizable player for your video and music in
  phone.  The video and music player with most customizable space.  
Convenient gestures to control. Advanced media folder settings, you can 
 set including and excluding folders — in ANY DEPTH. Not only one level 
 under /sdcard now.
8. 
VitalPlayer
VitalPlayer  supports almost all video
 and audio codecs. This powerful software  codecs provide smooth quality
 video. System mode play(hardware codec  use) , SMI,SRT support – 
Brightness control , Resume play previously ,  Gray screen(software 
codec only) , Various font size & color &  type and so on.
9. 
RealPlayer
Entertainment  on your Android. 
RealPlayer is one of the best Android apps to enjoy  your music, videos,
 and photos. More user-friendly than ever, RealPlayer  includes an 
intuitive user interface, playlist editor, widgets,  searching, content 
folder selection, fast scrolling, and a ton of other  features to make 
your media experience more enjoyable.
10. 
DicePlayer
Diceplayer  is a HW accelerated Media 
player for android. It use HW video decoder  at various containers and 
audio codecs combination. Dual Core/High end  devices ( Sensation , 
Galaxy S/S2 , Nexus-S ) can play 720p MKV/AVI.  Diceplayer drains less 
bettery than SW based players.