Anyone with one of the Apple products in his hand would know its biggest disadvantage over almost all similar devices. If you want to watch a video in any format other than wmv or mp4 on these gadgets, you are out of luck. But VLC comes to your rescue as always(as in PC and Macs). With this app you can watch almost any video on your idevice.
While the VLC app is not readily available on the iTunes App Store, it can be downloaded from the Cydia repository directly or installed through iFunbox on a PC/Mac. But before of all you need to jailbreak your idevice. You may find the jailbreak from redsn0w. If you want to install an untethered jailbreak then you will have to update your iOS to 5.0.1 before jailbreaking. Otherwise a tethered jailbreak will be installed on your device. There are several videos on youtube to jailbreak any idevice.
Once you have jailbroken connect to a wifi hotspot, find the cydia app and launch it . It will download the repositories and database. After it is done, search for ‘VLC’ and it will show the app in the results. Download the app and it will be installed automatically. After that you can transfer videos to your iPhone/iPod/iPad through iFunbox. It is a free software available here. Just extract it and run. Inside iFunbox you will have full control over your idevice. You can access all the system files too. Now select the raw file system and go to /Var/mobile/Media. You can transfer videos from your computer to your idevice by copying videos of any format to the Media folder through iFunBox. A point we would like to make here is that iFunBox supports drag and drop directly.
If you don’t have wifi nearby then no problem. You can also install the VLC app through iFunBox too. Just download the VLC app on your PC and copy it to Cydia App Install folder in iFunBox. After that just reboot and respring your idevice and it will be installed automatically! However if you are on a tethered jailbreak then you have to boot your idevice using the jailbreak software (redsnow).
But we have to warn you that even if jailbreaking is legal, it may damage your device(it may be bricked) which rarely occurs and we are not responsible for what happens to your device. We have tried it ourselves and hence we are showing it to you. Another catch here is that you can watch only standard definition videos in common video formats. HD videos are not supported and large videos(large files) may not play at all too.
UPDATE- As one of our readers pointed out, there are a few free alternatives such as flex:player, Gplayer lite etc. which can be downloaded from the app store directly and the videos can be transferred via iTunes file transfer too. It is just that I was so used to VLC that I overlooked the recent released in the App Store. We thank Mr.Kailash for the valuable comment.